# Correct timing on a mild 400



## ylwgto (Oct 27, 2009)

So I've been battling with optimal timing and carb issues for a year on my 66 ('68 mild 400, Holley DP 750 electric choke vacuum secondaries, #16 heads, MSD pro billet dist with 6A box, headers).

I've read the forums up and down about initial timing and total timing, but this is one aspect of the car that I have poor experience in. Every time I try and tune the car it feels worse and I do not have access to a dyno or strip to actually subjectively test changes.

I recently took it to a muscle car "shop" to have the timing set and carb "tuned" and it came back to me running worse (rough idle at start up until electric choke opens), slow throttle return (the fast "brap" is gone) and what seems like a general loss of power throughout the RPM range.

Here is what the shop said after I told them Pontiac's generally like 36 degrees of total timing at 2800ish RPM:

"Ryan, the car is at 11 degree advance at idle, and 28 degrees at 2,200 RPM with no vacuum advance. If you want more than 28 degrees at cruise, the distributor would either have to be re-curved, or try hooking up the vacuum advance to see how it reacts. More advance than 28 could cause pinging."

What to make of this? Any suggestions on what to do next? Any suggestions for a reputable place to get the engine set up right around the Bay Area CA?


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## PontiacJim (Dec 29, 2012)

ylwgto said:


> So I've been battling with optimal timing and carb issues for a year on my 66 ('68 mild 400, Holley DP 750 electric choke vacuum secondaries, #16 heads, MSD pro billet dist with 6A box, headers).
> 
> I've read the forums up and down about initial timing and total timing, but this is one aspect of the car that I have poor experience in. Every time I try and tune the car it feels worse and I do not have access to a dyno or strip to actually subjectively test changes.
> 
> ...


The shop you used has no clue on how the vacuum advance works, let alone how to set timing and timing curves on a Pontiac. They should not be touching older cars. Hope they did not charge too much.


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## ylwgto (Oct 27, 2009)

even to me with limited experience it sounded like BS.

So point me in the right direction


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## PontiacJim (Dec 29, 2012)

ylwgto said:


> even to me with limited experience it sounded like BS.
> 
> So point me in the right direction



For starters, you need a good "dial back" timing light.

An accurate tachometer to measure engine RPM's.

Then a spring kit for the distributor weights, possibly an advance bushing kit if the MSD distrib. uses these.

Then we can go from there. You will be using the vacuum advance connected to a direct port source and that too will be dialed in for your engine.

11-12 initial could be fine, but the vacuum advance needs to be hooked up so it adds another 10 for 21-22 initial. You could also bump up the initial, but limit the vacuum, and still try for 21-22 degrees. The key is how hard it starts. When initial is too advanced, it'll start real hard and the starter will struggle to spin the engine - bad thing. With the initial not advanced enough, you lose that crispness from the throttle which I think you now have.

Not a fan of 36 degrees total, but it could certainly work. I prefer to go around 32 to start and then move up or down based on response and pinging. If you have flat tops and #16 heads, then you have high compression near 10:1 and should be using high octane gas or octane booster. If you have reduced the compression with dished pistons to nearer 9:1, then better.

So we need to know this info as well as this plays into timing curves and total timing.


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> even to me with limited experience it sounded like BS.
> 
> So point me in the right direction


PM me bro and we can talk on the phone about it. I'll teach you everything that I know. I learned it here last week. But seriously, I have been on a mission with this for the last two months and I'm just wrapping it up myself.


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## Lemans guy (Oct 14, 2014)

Solid advice, yes guys always talk about timing from the back to the front,...like the shop “11 base and 28 at 2200 Rpm...if you want more cruise..blah blah”...

this is backwards....PJ and Army are setting you right....

The first number you want to know is your Centrifigal advance total...you get that with a dial back timing light...or on the bench with a protractor...or a distributor machine...









How to Optimize the Centrifugal Advance in Pontiacs - High Performance Pontiac


Check out this low budget way to determine and settle Pontiac centrifugal advance in your point type distributor. You can do this procedure in one or two hours!




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Once you know that number subtract it from 36 to get your base setting. PJ like to subtract from 32, just more conservative approach. Split it and subtract from 34....so if your Centrifigal was 22 degrees.....34 - 22 = 12......set base at 12. Now add 10:degrees from a vacumn can hooked to full manifold vacumn for 22 degrees idle timing and 34 degrees total timing.

vacumn is never considered part of total timing because when the Pedal is at WOT there is no vacumn and therefore no vacumn advance.

you max timing available for cruise will the be 34 + 10 for 44......44 to 48 is what you want on todays.

Now for the thing that you do last, that everyone puts first and confuses timing. Is the rate that the springs allow this Centrifigal number to be “all In” since you have 22 Centrifigal in this example it is how fast the springs get that 22 to go from 0 to 22.....

Centrifigal advance is ONLY dependent on RPM’s so the strength of the springs decides how fast that occurs...about 3000 RPM is good to shoot for and normally you have to mix the springs, start with one light and one medium and see how it goes.

Go slow and your car will run great


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## armyadarkness (Dec 7, 2020)

AND! I will say, as most will mention, each car and each dizzy is different! I've had 3 dizzys in my 400, since December, and they all had unique settings, to get the same results. So... Don't generically trust internet advice or advertised specs. Trust your pants and ears.

I have a billet MSD which runs off a Mallory High Fire.

The dizzy has adjustable mechanical timing and it was factory set at 21.

The can is adjustable and it was set at 10.

I set my base timing at 18, so with the can disconnected, at 3000 rpms, I shouldve had 39 degrees, but I only had 36.

I then plugged in my can, and I shouldve had 28, but I had 30.

I'm running 93 octane on a fresh 400 with 670 heads and flat pistons, and it's still not pinging. So, if the car starts and idles great but I want to advance the total more, then I need to swap in a new bushing... but since I already know that they're "not perfect"...

If my 21 degree bushing is 3 degrees to short, maybe my 24 degree bushing will be 3 degrees too far! Meaning...

If I were to only trust specs, without proving, listening, and feeling, then I'd be going in circles.

Get a good dial back timing light... Innova. Less than $100 on Amazon. Keep a log book of what you have and what you're trying... And don't touch the carb anymore until the timing is right.


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## Old Man Taylor (May 9, 2011)

Good info and bad info from your tuner. I had a 400 with #16 heads as well. If nothing was done to the pistons when the engine was rebuilt then you are running about 10.25:1 actual CR. In CA we can only get 91 Octane. If you set your timing for best performance you will break something. The other issue is how your timing is created. Eleven initial and 28 total means your only getting 17 out of the distributor. The Pontiac distributors I used had 24 (12x2) in the distributor. The factory set the initial at 6 for a total of 30, but they ran best at 36 (12 initial). The most initial I ever ran on a streetcar was 16. That was a hybrid 428. The distributor must have been more like 20, but I don't remember for sure. That engine had #31 heads. Your car will like a lot of initial, but it will get hard to start. Your key challenge right now is figuring ot your CR, or just advancing the timing until it pings too much and then backing off.


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## ylwgto (Oct 27, 2009)

ok, wealth of info here. Thanks all!

Talking to a friend, he told me dial back lights do not play nicely with MSD boxes (I have an old 6A). Any truth to this? If not, I'll try and buy one and dig into this a bit.

Other issue is my carb settings....another area that I am not too good at. 

As far as CR, I cannot remember what my pistons are (flat or dished) as I refreshed the engine about 20 years ago. Any way to tell with a scope through the plug hole or something? I did have the heads rebuilt back then to harden the valve seats for modern gas and an had an angle job. Beyond that they are pretty stock. No pinging with current settings on CA 91 octane. But, I had been having dieseling or "run-on" issues before I redid my cooling system, and seem to remember that is related to timing too advanced or retarded..I forget.

Basically, I'm just not sure where to start. timing or carb issues. 

oh, and BTW my TH400 is a limp turd that short shifts to 3rd almost immediately at 1200rpm. Cannot figure that out either. joy. I'd love to get back to smokin the meats from 1st through third like i was doing before I tore into it with these upgrades


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## Lemans guy (Oct 14, 2014)

Straight advice as always from Mr. Taylor.....set timing right first then dial in the carb.

th th400 vacumn modulator is adjusted with a screwdriver from under the car. This will spread out your shift points ar light throttle

The Th400 governor is also easily accessible from under the car and easy to change the governor weight, Trans suppliers like TCI all sell small inexpensive governor kits.

easy to do, once you take a look at then..


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## Lemans guy (Oct 14, 2014)

https://www.coanracing.com/mwdownloads/download/link/id/64/



Here are good instructions from Coan racing they sell the kits,...here is a B&M kit from summit









B&M Governor Recalibration Kits - Free Shipping on Orders Over $99 at Summit Racing


Find B&M Governor Recalibration Kits and get Free Shipping on Orders Over $99 at Summit Racing! B&M governor recalibration kits will allow you to adjust the shift points of your transmission after it is installed in your vehicle. These kits are very useful for transmission swaps, or if you have...




www.summitracing.com


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## Old Man Taylor (May 9, 2011)

Run on has nothing to do with timing. It happens when you shut the key off and there is no spark.


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## Lemans guy (Oct 14, 2014)

*Yes and overheating can add to run on as you have seen. Also a throttle plate that open too much can cause run on. Open the mixture screws a tad and close the throttle plate a tad back and forth to keep your mixture correct but not too much throttle plate*


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## ylwgto (Oct 27, 2009)

I adjusted vacuum modulator (2 full turns clockwise) and will see if that helps. I changed it when I did a filter/fluid change a couple months ago, so hopefully this is the culprit (have not messed with the governor or kick down switch...fingers crossed).

Adjusted curb idle and idle mixture a bit. It was idling too high and smelled rich. Its warmer here and car has been running better, we'll see.

My MSD distributor does not have a vacuum advance. It is a Pro billet model with a 6A box controlling the spark. So, not sure where to begin with the timing now given the prior comments about individual timing components.


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> I adjusted vacuum modulator (2 full turns clockwise) and will see if that helps. I changed it when I did a filter/fluid change a couple months ago, so hopefully this is the culprit (have not messed with the governor or kick down switch...fingers crossed).
> 
> Adjusted curb idle and idle mixture a bit. It was idling too high and smelled rich. Its warmer here and car has been running better, we'll see.
> 
> My MSD distributor does not have a vacuum advance. It is a Pro billet model with a 6A box controlling the spark. So, not sure where to begin with the timing now given the prior comments about individual timing components.


This has been coming up a lot, with that dizzy. I actually bought the same one but returned it prior to install, just for that reason. The weird thing is... MSD makes the exact dizzy, a pro billet, controlled by a 6a, for Summit, with the vac can, but they don't have one branded MSD! So.... I bought the Summit one and I love it.

Must of these guys will tell you that your car will run much cooler and crisper with the vac can, and that it's just good to have.









Running hot - seemingly out of options


And yes I use the Mr Gasket thermostat, too. I just drill 3, .125 holes in it. I can tell you that my last car was a 70 vette, and they pretty much have the worst rep in the entire GM lineup, for cooling. But with those few small mods and a thorough cleaning, it was always super cool!




www.gtoforum.com


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## armyadarkness (Dec 7, 2020)

Thats another thread discussing your dizzy and timing


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## PontiacJim (Dec 29, 2012)

ylwgto said:


> I adjusted vacuum modulator (2 full turns clockwise) and will see if that helps. I changed it when I did a filter/fluid change a couple months ago, so hopefully this is the culprit (have not messed with the governor or kick down switch...fingers crossed).
> 
> Adjusted curb idle and idle mixture a bit. It was idling too high and smelled rich. Its warmer here and car has been running better, we'll see.
> 
> My MSD distributor does not have a vacuum advance. It is a Pro billet model with a 6A box controlling the spark. So, not sure where to begin with the timing now given the prior comments about individual timing components.


OK, so you just learned that too high of an idle RPM is what causes "run-on" or "dieseling." The primary throttle plates are cracked open too much at higher idle settings allowing gas to be drawn into the engine through the idle circuit and the heat still left in the cylinders ignites the air/fuel mixture.

Adust your idle screws in until the engine runs rough, then back out just enough to smooth out. Then do the other side the same. Now once adjusted and engine seems to be running smooth, re-adjust one more time. Get idle RPM as low as you can looking to hit around 650 RPM's. You can slowly drop/adjust the idle speed screw that will adjust the throttle plates open/closed at idle. If the engine starts to run badly/rough as you drop the idle screw adjustment, turn each idle mixture screw open 1 /2 turn to add a little more fuel to compensate for the lower idle RPM and see if that smooths it out. Better to run a tad bit rich when at idle than to run a higher idle RPM and experience "run-on." If the engine ever does "run-on," turn the key back on to keep the engine running smooth, then drop in gear, and then shut off the engine - weight of the converter and trans in gear should be enough to make the engine quit. Not the way to do it, but far better than "run-on" and taking out rod/crank bearings, or worse.

The Pro distributor you have does not feature the vacuum can - I checked. Not a good thing as the vacuum can is really a big plus on a street car. Don't need it for a race car and I have used dual point distributors way back that did not have vacuum advance - but this was near the tail end of good octane/leaded fuel as well.

I found an article on setting up your Pro Dist. that may help. In your case, I might try and advance the Initial timing as much as possible and then use the limiting bushings to keep the Total closer to 32-34 degrees, and you can play around from there. Read the article where it says you can advance the Initial, but if it cranks hard to start, it's probably too much - so you may have to experiment. The more Initial advance you put into it, the higher the RPM's at idle will go - so you may have to re-adjust the idle RPM screw as well as idle mixture screws again to get things balanced out.

You can also play with the springs which will create a "timing curve," ie as the RPM of the engine goes up, the mechanical timing will correspond and increase. Depending on the springs you use or mix/match, You may want to shoot for Total of 32-34 degrees at around 2,800-3,000 RPM's. Listen for ANY detonation. ANY detonation is a bad thing. You can re-adjust timing and see if that will get rid of it, or you may have to boost fuel by using higher Octane gas or an octane additive. If you hear ANY detonation (typically at full throttle/load), back out of the gas pedal and ease back home to make your adjustment.

You can play around with the Pro Dist., but I honestly am not sure how it will turn out in the end, but give it a go. *Lemans guy* will most certainly add to this as well. The vacuum advance feature has helped others in the past to get their cooling systems down in temps.









How to Set Up an MSD Distributor Part I


Installing MSD’s Pro Billet distributor will give you access to a variety of tuning and timing features in your engine. Part I of this new series covers the basics.



www.racingjunk.com


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## ylwgto (Oct 27, 2009)

armyadarkness said:


> This has been coming up a lot, with that dizzy. I actually bought the same one but returned it prior to install, just for that reason. The weird thing is... MSD makes the exact dizzy, a pro billet, controlled by a 6a, for Summit, with the vac can, but they don't have one branded MSD! So.... I bought the Summit one and I love it.
> 
> Must of these guys will tell you that your car will run much cooler and crisper with the vac can, and that it's just good to have.
> 
> ...



Interesting. So it seems there is no way to adapt a vac can to that distributor...


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## ylwgto (Oct 27, 2009)

Just read PJ's post...super helpful. Thanks.

I'll consider playing with what I got vs. sourcing another distributor with vacuum advance capability and will try to tune my carb (again) in the meantime. I suck at it and usually mess things up, but practice makes perfect...


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> Interesting. So it seems there is no way to adapt a vac can to that distributor...


Correct. It said that much, right on the box! But it's even more perplexing... why they'd make it with a vac can for Summit, but not for themselves.


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> Just read PJ's post...super helpful. Thanks.
> 
> I'll consider playing with what I got vs. sourcing another distributor with vacuum advance capability and will try to tune my carb (again) in the meantime. I suck at it and usually mess things up, but practice makes perfect...


I've literally set my timing at least 20 times since December, and the carb aint far behind. Lots of frustration... but also lots of knowledge. Now that I understand whats going on, I can control it, vs the other way around. Yes, I still get jammed up all of the time, but I experiment, take notes, research, and hit it again.

Last night I discovered the woes of a CD ignition box... MSD 6A. Makes the new digital, dial back timing light go crazy!!!!


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## armyadarkness (Dec 7, 2020)

BTW, those adjustable cans really do suck! I have 18 degrees base and the can was bringing me up to 33. I wanted to dial it back to 28, but it took so many turns to get it lowered. They're very inconsistent


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## O52 (Jan 27, 2019)

No need for a special dial back timing light. Just buy a timing tape.









PONTIAC Summit Racing SUM-165597 Summit Racing™ Timing Tape | Summit Racing


Free Shipping - Summit Racing™ Timing Tape with qualifying orders of $99. Shop Timing Tape at Summit Racing.




www.summitracing.com


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## ylwgto (Oct 27, 2009)

armyadarkness said:


> I've literally set my timing at least 20 times since December, and the carb aint far behind. Lots of frustration... but also lots of knowledge. Now that I understand whats going on, I can control it, vs the other way around. Yes, I still get jammed up all of the time, but I experiment, take notes, research, and hit it again.
> 
> Last night I discovered the woes of a CD ignition box... MSD 6A. Makes the new digital, dial back timing light go crazy!!!!



yeah, I asked a friend a few days ago about dial back timing lights and he said because I have a 6A box it won't work. was about to order one, so I'm glad I held off. My distributor is the PN 8563, so yeah...no vacuum advance option.

with the tape you put on the balancer, it has to correspond to the diameter of the balancer, right? And how do you know where to lay it on?


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## armyadarkness (Dec 7, 2020)

Well... My original dial back light worked fine.... It was when I bought the high tech digital wonder, that it went crazy. The analog light worked fine.


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## O52 (Jan 27, 2019)

I've always lined up the hash mark on the balancer with the zero on the tape. You then use the 0* mark on the timing cover as a point of reference. But before you do that you need to insure that the 0* mark and the hash mark line up with #1 top dead center. Its good practice to do with any floating (rubber mounted) balancer. Then paint two white lines across the front of the balancer to verify it hasn't moved over time. Even my 07 Cadillac has the marks from the factory.


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## PontiacJim (Dec 29, 2012)

ylwgto said:


> yeah, I asked a friend a few days ago about dial back timing lights and he said because I have a 6A box it won't work. was about to order one, so I'm glad I held off. My distributor is the PN 8563, so yeah...no vacuum advance option.
> 
> with the tape you put on the balancer, it has to correspond to the diameter of the balancer, right? And how do you know where to lay it on?



The best way to do this is to use what is called a Top Dead Center (TDC) tool that you screw into the #1 plug hole and then turn the stop in. Pull all the spark plugs to make turning thr crank over by hand much easier - no compression fighting you.

Remove the distributor cap and turn the engine over as you watch the rotor as it lines up near to the #1 cylinder position on the cap. Watch for the balancer timing mark to come up to the timing tab. Stop turning just before coming up on the timing mark - and assuming the balancer is correct - the #1 piston should be almost at TDC. You should be able to shine a light into the spark plug hole and see the top of the piston.

Install the TDC tool into the spark plug hole and continue to rotate the crank by hand until it comes against the stop. Make a mark on the balancer where the timing pointer shows. Now rotate the engine by hand in the opposite direction until the piston again hits the stop. Mark that position from the timing pointer on the balancer. Find the mid-point of the two marks and mark you balancer as that is the exact TDC.


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## ylwgto (Oct 27, 2009)

Thanks PJ. I'll try to find some time to experiment with this. I just instaled a new balancer as part of my front engine refresh and am not sure there is a timing mark on it, but using the TDC tool sounds like the best way (maybe I'll get a peek at my piston too to see if it is flat or dished). Thanks


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## armyadarkness (Dec 7, 2020)

I got this a few months back... Cheap... Uses your smart phone... It's a game changer.








Wireless Endoscope, DEPSTECH Upgrade 5.0MP HD Inspection Camera, Scope Camera with Light, 16 inch Focal Distance, Semi-Rigid Snake Waterproof Borescope with 2200mAh Battery for iPhone & Android-16.5FT: Amazon.com: Industrial & Scientific


Wireless Endoscope, DEPSTECH Upgrade 5.0MP HD Inspection Camera, Scope Camera with Light, 16 inch Focal Distance, Semi-Rigid Snake Waterproof Borescope with 2200mAh Battery for iPhone & Android-16.5FT: Amazon.com: Industrial & Scientific



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## armyadarkness (Dec 7, 2020)




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## Lemans guy (Oct 14, 2014)

Y could not be described better than PJ and Army have discussed. Lionlike them lot’s of people dismiss Vacumn advance because one they don’t understand it or two they have seen fast cars and race cars without it.

about 36 total base and Centrifigal timing is all you get on these engines, yes can take 38 total a few 40. But when lean mixtures are present at idle and light throttle cruise, think a lot of youroperating time on a street car your timing compared to mixture is way inefficient. You will have to give pedal than someone with the correct setup to get not nearly the same benefit.

With a 10degrees from vacyou can then get 46 degrees at light throttle cruise and 10 more at idle. For a cooler running car, better gas mileage ,more efficient more power on a light pedal and you don’t give up anything at WOT cause Vacumn drops out.

Next time you see a computer tuned EFI you will see that some have a provision for “Vac advance” yes the computer can add just when the vac would at idle and at Leigh’s throttle.

No other way to get it...a computer or a vac can.


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## ylwgto (Oct 27, 2009)

Ok, I'm sold on the benefits of vacuum advance. 

Were I to swap distributors, any recommendations? Not keen on dropping $450 on another MSD, but I would like to keep my 6A box and I just made new plug wires for my female style current MSD cap.


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## ylwgto (Oct 27, 2009)

armyadarkness said:


> I got this a few months back... Cheap... Uses your smart phone... It's a game changer.
> 
> 
> 
> ...


now that is indeed a cool tool...I could use that for the bike building I do as well.


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> now that is indeed a cool tool...I could use that for the bike building I do as well.


I'm old skool, so I use the mirror a lot, but this GEM has really been a life changer. It has an onboard LED light, so you can easily go into your cylinder and see your piston, or down the carb, behind the dizzy, etc.

O use it as a bore scope on firearms, inside walls looking for pipes and wires... and on a few occasions, after a night of drinking, I've even played doctor with it. The girlfriend was not amused.


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> Ok, I'm sold on the benefits of vacuum advance.
> 
> Were I to swap distributors, any recommendations? Not keen on dropping $450 on another MSD, but I would like to keep my 6A box and I just made new plug wires for my female style current MSD cap.


I swear that I posted a link to this already... but...

This unit is NOT READY TO RUN! It uses your 6a box and is pre wired for it.








1967 PONTIAC GTO Summit Racing SUM-850084 Summit Racing™ Billet Distributors | Summit Racing


Free Shipping - Summit Racing™ Billet Distributors with qualifying orders of $99. Shop Distributors at Summit Racing.




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## armyadarkness (Dec 7, 2020)

So now....

Go read this, and hopefully, everything that everyone here said, will now make a Hell of a lot of sense.


https://static.summitracing.com/global/images/instructions/sum-850084.pdf


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## ylwgto (Oct 27, 2009)

armyadarkness said:


> So now....
> 
> Go read this, and hopefully, everything that everyone here said, will now make a Hell of a lot of sense.
> 
> ...



Indeed it does. I'll have to research if my existing MSD cap (female) would pop right onto that summit unit since I just spent $75 on new wires and 2 hours cutting and looming them. 

I'm gonna have to work up the bravery to stab a new distributor in, but between the comments here and YouTube I think I can handle it. BUT, gotta to the TDC tape method before anything to establish the baseline. I'll circle back one I have the nerve and time to tackle this. 

Thanks for all the info everyone.


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## Baaad65 (Aug 29, 2019)

I've seen that camera scope somewhere before...oh ya right before I went under at the doctor's office 😉


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## Lemans guy (Oct 14, 2014)

If you are keeping that ignition box you have to get one that will work with that, Petronix sells distributors for under $300 that work with ignition boxes, Summit does as we,, if you had no ignition box an AD deltoid HEI are available for under $200. And a points distributor( meaning narrow body can also be used with an electronic switch conversion, like Petronix conversion units. They make full distributors as well. MSD are good but cost more. Lots of guys love them, but it depends what you are going for.

High demand RPM racing, or fun street driving.......no way is wrong.

google this hot rod article

HEI vs Points shootout. You can skip,all the blather of all the companies telling you why there box is better, some have good arguments and all products offer something. But go down to the Dyno sheet and compare the HP and Torque at various speeds of the 3 types of distributors they tested.

Also look at 5200 RPM where you have HP and Torque crossing...do you major differences?

Just know that performance products do help some but maybe at RPM’s and demands you don’t use, but maybe you do.
An original points distributor on your 68, even keeping the points, if curved correctly will keep up with any other street car.....it willl get down to gears and drivers and fuel etc.

So a lot of ways to go. MSD are great products I use there cap and rotors with brass terminals exclusively.


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## PontiacJim (Dec 29, 2012)

I don't know anything about Speedmaster products, but they seem to offer an assortment of parts for the Pontiac. Here are some distributors with good pricing.






Ignition & Electrical > Ignition Components







speedmaster79.com


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> Indeed it does. I'll have to research if my existing MSD cap (female) would pop right onto that summit unit since I just spent $75 on new wires and 2 hours cutting and looming them.
> 
> I'm gonna have to work up the bravery to stab a new distributor in, but between the comments here and YouTube I think I can handle it. BUT, gotta to the TDC tape method before anything to establish the baseline. I'll circle back one I have the nerve and time to tackle this.
> 
> Thanks for all the info everyone.


Well, I brag about many of my skills, but if there's one thing I'm an expert about, it's putting a distributor in wrong. So, you can keep me on speed dial.


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## armyadarkness (Dec 7, 2020)

ylwgto said:


> Indeed it does. I'll have to research if my existing MSD cap (female) would pop right onto that summit unit since I just spent $75 on new wires and 2 hours cutting and looming them.
> 
> I'm gonna have to work up the bravery to stab a new distributor in, but between the comments here and YouTube I think I can handle it. BUT, gotta to the TDC tape method before anything to establish the baseline. I'll circle back one I have the nerve and time to tackle this.
> 
> Thanks for all the info everyone.


That Summit dizzy is made by MSD, and the cap is the same... It even comes with the retainer, etc. I use a Mallory Hy Fire with mine. It's an MSD 6a, the boxes are all the same now


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## PontiacJim (Dec 29, 2012)

ylwgto said:


> yeah, I asked a friend a few days ago about dial back timing lights and he said because I have a 6A box it won't work. was about to order one, so I'm glad I held off. My distributor is the PN 8563, so yeah...no vacuum advance option.
> 
> with the tape you put on the balancer, it has to correspond to the diameter of the balancer, right? And how do you know where to lay it on?


Just to confirm. I pulled up the instructions for the MSD6AL box and it did state that you could not use a dial-back timing light.

However some say no issues, and I found this on the Corvette site:

"I also had a few problems with my timing light and my MSD 6A electronic ignition : the index on the harmonic balancer was always moving by a few degrees, making the reading impossible.
I finally tried this with success : Instead of using the car battery to supply the timing light, I used an external battery ( An external 12V power supply could also be used ) to supply energy to my timing light.
I only used the #1 cylinder ignition wire to give a proper signal to the light and it worked great !
It seems that the CD electronic ignitions create some small perturbations on the electrical systems of the car, and they are sometimes detected as a false signal by the timing lights.
Using a separate supply addresses this issue."

From Holley/MSD - "It is recommended that you * NOT * use a digital or 'dial-back' timing light when using an MSD CD ignition. _A 'bare-bones', indictive light is the recommended light and even then you might want to isolate the power supply to the light by utilizing a spare battery or another car pulled up along side your vehicle to power the timing light."_ * PJ*: Which is what the guy in the post above did and it worked for him using the dial-back.

*AND THIS:*

About the best light for MSD boxes is the craftsmen dial light at Sears. thats what all the guys have around here. i have a 6AL on one car and a 7AL on the firebird, never have any problems.

My Craftsman dial back light works perfectly with MSD....... 

I use a Sears Craftsman timing light with the advance dial on back, & had no problems with my MSD 6A set-up. It also works OK with the Davis DUI ignition even though Davis says it may not. 
I use a Craftsman dial-back with my Mallory CD ignition and it works fine.

Here is what I use on my MSD Digital 7+: Craftsman Timing Light, Inductive 
Sears item #00921027000 Mfr. model #21027 
It works on Pro Mags too. 


*AND HERE ARE SOME TIMIMNG LIGHTS:*









4 Best Timing Light for MSD Ignition and Cable Reviews 2021 | Rx Mechanic


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## ylwgto (Oct 27, 2009)

PontiacJim said:


> Just to confirm. I pulled up the instructions for the MSD6AL box and it did state that you could not use a dial-back timing light.
> 
> However some say no issues, and I found this on the Corvette site:
> 
> ...



Thanks PJ. Super helpful. Mine's an old 6A, so maybe it'd be fine.


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## armyadarkness (Dec 7, 2020)

And my light is the 30-year-old craftsman dial back, so I guess that's why it works


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## Lemans guy (Oct 14, 2014)

I always use a spare shop battery I keep charged up for timing light. Really just for the convenience of not having to drape the leads all over the front of the car and trying to miss fans and belts etc. I have had enough timing light wires cut doing that or even burning them on the manifold etc.

I just roll a tool cart up next to the car with the battery on it, and hook the two power leads on it. Do it with Tach dwell meters as well, smoke machine, oscilloscope etc. a spare charged up battery is a good tool to have and from what you guys are saying may even help on MSD boxes.

I know PJ likes MSD a boxes and many racers do. I just see them as adding multiple spark event that covers bad timing at low speed. A little “Voodoo” to me. I think at higher RPM racers want the strong spark consistently and they have some benefit there just like an HEI system does.

Street cars, not so much. A strong spark from a good setup system at the right time with the right AFR will make a strong runner,.....with points, Or electronic switching. Multiple spark really won’t matter there.

I remember Mr. Taylor saying the Box helped him with real radical cams at idle. So it couldbe applicable there. But I have set up some real radical roller cams without them and made them smoooth runners with just perfect timing.


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