# 1971 400 stroker build



## soberjoe (Nov 28, 2016)

I delivered a ‘71 long block to the local Pontiac guru today, having him build a 461 stroker over the winter.
The block has ‘71 #96 heads and my builder believes that these heads, with some porting and clean up, will work really well on a 461 built to somewhere around 425hp
What’s the consensus here?
Are the iron #96 heads a decent (cost effective) choice?
Is there anything in particular that needs to be attended to?

I realize that there are likely 4 novels worth of possible replies here, lol, but I needed to ask the question  

Thanks everyone 


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## Old Man Taylor (May 9, 2011)

I think 425 is very conservative.


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## BearGFR (Aug 25, 2008)

Old Man Taylor said:


> I think 425 is very conservative.


Agreed. A great deal will depend not only on how well the heads flow but on the cam profile you choose. The first incarnation of my 461 build made 500 hp / 535 lb ft on the dyno at break-in with the factory iron intake, 800 cfm QJet, 72 cc iron heads, 9.5:1 compression, and a solid roller that was really somewhat mild for a roller (236/242 @ 0.050, 110 LSA, 0.600 net lift at the valves) and it was running a tad lean at 13.7:1 air/fuel at the time. That incarnation had NO quench at all in the cylinders because of some really ugly things I had to do to it in order to get compression down to 9.5:1 for pump gas. The pistons had >round< dishes in them (so zero quench pad area) combined with 0.075" thick head gaskets. I had on it at the time a set of gen-u-wine #722 '69 RA IV heads that I really really wanted to run, so that's what it took. 

I ran out of time to play with it on the dyno, but I'm guessing there would have been "more in it" with a richer fuel mixture and perhaps a little more timing.

Bear


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## soberjoe (Nov 28, 2016)

BearGFR said:


> Agreed. A great deal will depend not only on how well the heads flow but on the cam profile you choose.
> 
> Bear


Thanks Bear - I’m planning on a using a Butler/Ross or Butler/Eagle setup with my #96 heads and RAR RM-2 D-port exhaust manifolds.
I don’t have an iron intake so intake, carb and cam are all areas that I need to investigate.
I am all ears when it comes to advice 

I’ll be putting a built TH400 behind it and going back to the 3:55 gears (I have 3:90 in it now)

The car is my summertime daily driver so I’m not aiming for a 10 second strip car - just something a little beefier than my stock 400 that’s in the car now.

Any recommendations you may have on a cam, rockers and valve train recipe would be greatly appreciated.

Oh, my builder also recommends that I go with a Holley 850 VS

Joe


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## BearGFR (Aug 25, 2008)

soberjoe said:


> Any recommendations you may have on a cam, rockers and valve train recipe would be greatly appreciated.
> 
> Oh, my builder also recommends that I go with a Holley 850 VS


Holley 850... Is your builder a Chevy guy? 

The previous incarnation of my engine in my '69 that had the horrible quench properties was running a QJet, 3.50's (Moser 9"), strong TH400 - and it ran 11.80's at the track (in Drive, auto-upshifting at about 4800 - because I didn't yet have a rev limiter in it).

Plus, we also took it on the full Power Tour in 2013 which was from Arlington Texas to Concord NC - and back with zero problems. At 70mph with those gears and the converter I had in it at the time, 70mph was in the neighborhood of 3200 rpm, which was a little much. 

I "pre-emptively" converted the car to hydroboost braking out of concern for idle vacuum, but I needn't have worried as it turns out. That cam made 13-14 inches at idle as it turned out, probably because, being a roller, overlap wasn't all that severe. A flat tappet cam with similar duration would have been "worse" as far as idle vacuum. 

The rest of the story on that build is that after I got it all together and had been driving it for some time, it developed a crack near, but not through, the #6 exhaust seat and started leaking coolant into that cylinder. I tried once to have it repaired, but it didn't hold, so I ended up replacing them with a set of 72cc round port Edelbrocks. That let me go back to standard head gaskets, but the quench was still horrible due to those big round dishes. Even with that I was only able to get it "back" to 10.0:1 when I think with those heads it really should be at 10.5:1 

That incarnation - the cam I described in the previous post, the E-heads, QJet, and 10.0:1 with horrible quench is the combination that ran 11.80's in Drive. 

For my most recent build, triggered by a rocker arm going away and putting shrapnel through the engine (at least partially my fault if not 100%) - which is a whole 'nuther story - I "stepped it up" with quite a bit more cam, more compression, Northwind intake, and an AED HO 850 with annular boosters. I fought with that dad-blasted carburetor for 12 -- solid -- months trying to get it right in all operating regimes, so in my experience tuning a Holley is nowhere NEAR as easy as everyone claims. Out of the box it was "almost" right, the one exception being part throttle / light cruise - where it was running so rich that I had to constantly keep changing the oil because of all the raw fuel that was washing into the crankcase. Getting it to lean out "enough" at cruise without messing it up everywhere else is what took me 12 months to accomplish. That experience really made me wish that I'd stuck with the QJet, but I had convinced myself that the other changes I'd made meant the engine needed "more".

My personal experience running a solid roller valve train on the street is that with modern parts, you don't really have to adjust valve lash that often - maybe a couple times a year, under normal circumstances, as long as you use good parts and that includes lifters that have positive oiling to the rollers and needle bearings instead of relying on 'splash'. 

I'm hesitant to make specific cam recommendations because there are too many variables involved, but maybe sharing my experiences and results will give you some ballpark ideas.

Bear


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## soberjoe (Nov 28, 2016)

BearGFR said:


> Holley 850... Is your builder a Chevy guy?
> 
> The previous incarnation of my engine in my '69 that had the horrible quench properties was running a QJet, 3.50's (Moser 9"), strong TH400 - and it ran 11.80's at the track (in Drive, auto-upshifting at about 4800 - because I didn't yet have a rev limiter in it).
> 
> ...


Thanks again man - I’ll be picking your brain down the road, no doubt 

Joe


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## soberjoe (Nov 28, 2016)

So, I have decided to go with Butler’s HR 8022SP custom grind Comp cam.
Specs are 282/288 Advertised Dur. / 230/236 Dur. @.050” / .510/.521 Lift w/1.5 Ratio Rockers 112 LSA

The block is .040 over so it’s a Butler/Ross 462, and I’ve ordered the SD super brace kit as well.
Intake will be the Edelbrock Performer RPM that’s sitting behind my couch, and I just dropped the heads off to be ported, polished and rebuilt. I asked the machinist to aim for 220-240 cfm.
I’ve decided to stick with my 2004R as it’s built and works well, however I’ll have to change out the torque converter to something more suited to the build.
I’m going to go with a DUI ignition system.

I still have not decided on a carburetor.

And that’s where I’m at so far . . .

Joe


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## Lemans guy (Oct 14, 2014)

I use a Quick Fuel Technology (QFT) 780 VS.......Holley owns quick fuel...just go to Holley web and under brands click Quick Fuel....much more tunable than a standard Holley..

all the idle and high speed air bleeds are changeable mini jets, so are the PVCR’s, the vac secondary has the same springs to change, but also has a fine tune with a screw..

4 corner idle, see thru sight glasses, mine is jet coated black..called the Black Diamond to reduce heat....you will need an adapter to fit the intake like with a Holley..

all the parts are easily avaible direct from QFT.......when you have trouble with circuits, no drilling, you can change the air bleeds, etc.....check em out....just another way to go


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## soberjoe (Nov 28, 2016)

Thanks for the tips LeMans guy



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## O52 (Jan 27, 2019)

Or find an 800 CFM QJ off a Buick 455 or a Cadillac 500


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## Jim K (Nov 17, 2020)

Soberjoe,
Your block is identical to the one originally in my 71. For what it's worth, here's my two cents:
the #96 heads should work well for a stroker as the CC's are 96. The biggest issue will be their ability to breath enough. Not that they won't work, just keep in mind the dynamics of the motor around given RPM's. what's your stroke length??
If you dropped the heads off to be worked over, it might be worthwhile to take your intake to them to match your head ports to the eddy intake ports since the eddy RPM intake ports were designed around the taller RA IV series. For a stroker it's all about breathing and D ports were always a little short for capability in that department. 220-240 CFM is asking a lot of those particular heads. I've attached an online data sheet from Stan Weiss which put together flow data from a multitude of heads. I think the best flowing numbers from 96 heads came from a set of Nunzi ported heads.
The SD braces are certainly not a bad choice since Pontiac's are known to be weak for bracing in the lifter galley area. BUT unless you plan on running some wild stage 5 type of mechanical roller they might not be absolutely necessary. Have you run any data through a dyno sim program to give you ideas about projected HP/TQ? I've got a dyno sim program and would be happy to run some calc's for you based on your parts selection.
As for the cam selection, I'm not a fan of Comp cams. They've had a lot of issues around material from their supplier, but the specs you stated should give you good idle quality and good vacuum.
As for the carb choice. Everyone has their favorite. I've never run a Holley so I can't say anything about them. The 850 CFM size might be a little big unless you plan on running consistently above 5,000 RPM's. Just remember the bigger the carb on a given motor the less low end response you'll have. Wallace racing web site has some good calculators for carb sizing.
And that is my 2 cents.. Okay 2.5 cents..

Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software


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## soberjoe (Nov 28, 2016)

Jim K said:


> Soberjoe,
> Your block is identical to the one originally in my 71. For what it's worth, here's my two cents:
> the #96 heads should work well for a stroker as the CC's are 96. The biggest issue will be their ability to breath enough. Not that they won't work, just keep in mind the dynamics of the motor around given RPM's. what's your stroke length??
> If you dropped the heads off to be worked over, it might be worthwhile to take your intake to them to match your head ports to the eddy intake ports since the eddy RPM intake ports were designed around the taller RA IV series. For a stroker it's all about breathing and D ports were always a little short for capability in that department. 220-240 CFM is asking a lot of those particular heads. I've attached an online data sheet from Stan Weiss which put together flow data from a multitude of heads. I think the best flowing numbers from 96 heads came from a set of Nunzi ported heads.
> ...


Good advice Jim K, thank you.
I did bring the intake with the heads at the request of the guy doing the work for precisely that reason - port matching as best as possible. The exhaust guides will be machined to accept positive seals, and bronze guides fitted all around. Straight 7/16” studs will be used in place of the stock shouldered 7/16”-3/8” studs. 
At the end of the day, if he gets those heads flowing 220cfm or better I’ll be more than happy I’m sure.
He likewise said that 850 was too big on the carb choice. He suggested 750 was more than ample, but he is not at all a fan of any of the Holley sub-brands like QFT, so I’m going to wait and see what he recommends after final-flowing the heads.

Final bore at .040 over is 4.16”
Stroke length is 4.25” with 6.800” rods.

Please feel free to plug the numbers in and see what you come up with,

Joe


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## Jim K (Nov 17, 2020)

Greetings Joe,
I ran some numbers through the sim program. I had to make a few assumptions around the head gasket. I didn't add any cam advance into the program, although your motor would most likely benefit from about 4 degrees advance install.
One thing I thought of this morning is that the Eddy performer RPM intake seems to be a very good intake with a good track record, BUT one issue is that it is 1.5" taller than a stock manifold, which by itself is not a bad thing but it might limit you on how tall your air filter can be. Most factory filters are around 3" tall but due to the intake, you might be limited to 2.5" or less for filter height. Reason i mention that is again, with a stroker motor, better breathing is a bigger deal than a stock stroke. Attached find some of the pages from the dyno sim. These numbers are indicative only and not exact. Exact numbers need to come from hooking the motor to a dyno and running it. I used the head flow numbers from the Nunzi port job since they were closest to what you are hoping to achieve.
I've attached the program results in PDF.


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## Jim K (Nov 17, 2020)

Here are some things that might be helpful. I am sure your guy doing your porting job is good at it and has most likely done it before, BUT.. Pontiac heads are different from other heads (as one would think) and to get the maximum flow, they respond better if certain aspects are followed when porting. also, the three angle valve job is usually different on a Pontiac than other. All of this comes from a book that's long been out of print called Pontiac high performance engine design and blueprint by Craig Hendrickson and Kern Osterstock.. Two Pontiac Gurus..


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## soberjoe (Nov 28, 2016)

Hey thank you for this Jim K - I appreciate the effort that you have put forth to lend a fellow goat owner a hand. I plan on sending this info - for reference purposes - to my head builder cause there's nothing to lose by sharing information 
And truth be told he ha only worked a few Pontiacs, so it can't hurt, lol


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## soberjoe (Nov 28, 2016)

The #96’s went on the bench today, getting a baseline before porting.










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## PontiacJim (Dec 29, 2012)

soberjoe said:


> The #96’s went on the bench today, getting a baseline before porting.
> 
> 
> 
> ...


Should be interesting. The average for stock heads seem to be around 205 CFM's. I did my own work on a set of 7K3 heads, used Ferrea RA IV length stainless steel 2.11" / 1.77" valves, and 2 angle valve job as my machinist said I had opened up the throats to where a 3-angle wouldn't work. I had 1 chamber flowed and this is what I got. My cam choice won't be .600" lift, but will be about .500" on intake and around .525" on the exhaust using 1.65 rocker arms.

______________INTAKE_______EXHAUST
Lift******************CFM**************CFM
.100*****************94.5****************48
.200*****************157****************107
.300*****************201****************142
.400*****************214****************167
.450*****************224****************173
.500*****************230****************178
.550*****************234****************178
.600*****************237


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## soberjoe (Nov 28, 2016)

PontiacJim said:


> Should be interesting. The average for stock heads seem to be around 205 CFM's. I did my own work on a set of 7K3 heads, used Ferrea RA IV length stainless steel 2.11" / 1.77" valves, and 2 angle valve job as my machinist said I had opened up the throats to where a 3-angle wouldn't work. I had 1 chamber flowed and this is what I got. My cam choice won't be .600" lift, but will be about .500" on intake and around .525" on the exhaust using 1.65 rocker arms.
> 
> ______________INTAKE_______EXHAUST
> Lift******************CFM**************CFM
> ...


I will post all of the before-and-after numbers when I get them 


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## Jim K (Nov 17, 2020)

Keep us posted Joe!.. Interested as to the numbers that come out before and after..


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## soberjoe (Nov 28, 2016)

Stock 96 D port baseline 

100—— 78.6 ——- 54.1
200—— 135.5—— 107.2
300—— 178.3—— 140.5
400—— 197.1—— 162.4
500—— 204.7—— 177.8
550—— 204.5—— 184.0
600—— 204.6—— 189.2
700—— 208.0—— 197.4


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## soberjoe (Nov 28, 2016)

Does anyone have a recommendation on a new water pump for this build? I was thinking of Flow Kooler #1649 or a Tuff Stuff #1475. 
Any thoughts one way or the other?


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## PontiacJim (Dec 29, 2012)

soberjoe said:


> Does anyone have a recommendation on a new water pump for this build? I was thinking of Flow Kooler #1649 or a Tuff Stuff #1475.
> Any thoughts one way or the other?


Personal opinion I suppose. Could not find a view of the impeller on the Tuff Stuff pump, but I am going to say it is similar to factory.

Flow Kooler seems to be liked by many, but seeing it flows way more at lower RPM's, I personally don't think I want that flow to ramp up too high as the engine's RPM's start to reach peak. Could the pump produce enough pressures to pop a water hose or exert unneeded pressures on a radiator? I think it may work much better on an engine having the pulleys that reduce water pump speeds at the lower RPM's so as not to pump too much pressures at higher RPM's. Would also seem to me that moving a higher GPM water pump must have the coolant flow within the block/radiator to work best. If not, would the pressure build up at the water pump create a power loss, or belt slippage, if the rest of the cooling system could not handle the high GPM water pump flow? I am no expert of course, and don't know if any real world testing has ever been done - might be interesting.

So this may be your call. Do some internet reviews on Pontiac as well as other makes.

I am going with the Milodon version which someone said was made/same as GNB. They also have the high flow T-stats which Tuff-Stuff also offers. I got my pump from Summit. Never had a cooling issue with any stock pumps, but your cooling system has to be matched to the engine's HP/TQ which is more about the radiator and air flow, not water flow - my opinion.






Performance Water Pumps From Milodon







www.milodon.com


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## soberjoe (Nov 28, 2016)

PontiacJim said:


> Personal opinion I suppose. Could not find a view of the impeller on the Tuff Stuff pump, but I am going to say it is similar to factory.
> 
> Flow Kooler seems to be liked by many, but seeing it flows way more at lower RPM's, I personally don't think I want that flow to ramp up too high as the engine's RPM's start to reach peak. Could the pump produce enough pressures to pop a water hose or exert unneeded pressures on a radiator? I think it may work much better on an engine having the pulleys that reduce water pump speeds at the lower RPM's so as not to pump too much pressures at higher RPM's. Would also seem to me that moving a higher GPM water pump must have the coolant flow within the block/radiator to work best. If not, would the pressure build up at the water pump create a power loss, or belt slippage, if the rest of the cooling system could not handle the high GPM water pump flow? I am no expert of course, and don't know if any real world testing has ever been done - might be interesting.
> 
> ...


Thank you Jim. I always appreciate your sage advice 
I’ll see what my builder suggests and take it from there. The reviews that I have read on the Milodon unit are positive and there’s no need to reinvent the wheel as they say, so I’ll keep that in mind.


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## Jim K (Nov 17, 2020)

Joe,
I think the same way as Pontiac Jim.. The Flow cooler puts out more volume which in turn would mean a faster flow of coolant in the motor (assuming the thermostat allows for higher flows). Coolant needs some time for the heat transfer to take place and the faster that coolant flows the less heat it will pick up from the heads and block. A better thought is to (a Jim mentioned) pay attention to how well the radiator is cooling which means having the correct fan and all the shrouds in place. My own particular motor is using a factory type water pump with aluminum heads and the motor runs cool at about 175-180 deg's. at the thermostat housing w/180 deg. stat. To help with cooling, you might consider a higher volume oil pump which would be better for the motor bearings/cam shaft. Again, just my two cents.


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## Jim K (Nov 17, 2020)

A couple of things i forgot to mention above.. That heat transfer is more critical on iron heads than aluminum and you might look into aluminum radiators. Aluminum dissipates heat faster/better than the old style copper ones..


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## soberjoe (Nov 28, 2016)

Jim K said:


> A couple of things i forgot to mention above.. That heat transfer is more critical on iron heads than aluminum and you might look into aluminum radiators. Aluminum dissipates heat faster/better than the old style copper ones..


Thank you for the replies Jim.
My ‘69 already has a 3” aluminum rad in it that works very well so I don’t really have any pressing concerns - I was actually more seeking exactly the type of advice that I have been receiving 
Flaws in my thought process and better directions to go in are what I’m after, and where better to find those than from a forum full of been-there-done-that Goat owners 


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## soberjoe (Nov 28, 2016)

The excitement is starting to build 
My first box of goodies arrived from Butler today 


















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## soberjoe (Nov 28, 2016)

Jim K said:


> Here are some things that might be helpful. I am sure your guy doing your porting job is good at it and has most likely done it before, BUT.. Pontiac heads are different from other heads (as one would think) and to get the maximum flow, they respond better if certain aspects are followed when porting. also, the three angle valve job is usually different on a Pontiac than other. All of this comes from a book that's long been out of print called Pontiac high performance engine design and blueprint by Craig Hendrickson and Kern Osterstock.. Two Pontiac Gurus..
> View attachment 140710
> View attachment 140711
> View attachment 140712
> ...


Hey Jim - I was just speaking with the guy working on my heads, and he was curious if you had any other cross-sectionals available - a lateral view into the back half of the head, or anything showing how much room to the water jackets?
We are, I think, at the point of 'good enough' for my application - rather than risk a costly oops. Just the same, he wants to be sure that he isn't leaving too much on the table if you know what I mean.

I ended up getting the QFT VS-780-SS and he has done some tweaking to it to bring out the best that it offers. We are now simply awaiting the arrival of my rotating assembly and top-end kit from Butler.
I have had the old girl out for a couple of rides in the country - maybe 300 miles total so far this spring.
Boy oh boy the excitement is starting to build . . .

Thanks again Jim - I truly appreciate all of your help - and hopefully once the current pandemic situation is under control and the border reopens I'll get a chance to shake your hand at a Pontiac Cruise-In somewhere,

Joe


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## PontiacJim (Dec 29, 2012)

soberjoe said:


> Hey Jim - I was just speaking with the guy working on my heads, and he was curious if you had any other cross-sectionals available - a lateral view into the back half of the head, or anything showing how much room to the water jackets?
> We are, I think, at the point of 'good enough' for my application - rather than risk a costly oops. Just the same, he wants to be sure that he isn't leaving too much on the table if you know what I mean.
> 
> I ended up getting the QFT VS-780-SS and he has done some tweaking to it to bring out the best that it offers. We are now simply awaiting the arrival of my rotating assembly and top-end kit from Butler.
> ...



Here is a scan from the HO Pontiac book looking at the side view. Not a lot of material at the top of the roof and you have to be careful - and remember there may be rusted metal in the coolant passages that can thin out the metal just because of age.

You can get flow by opening up the valve throats and blending the bowls, "boat tail" the valve guides, and narrow the pushrod bulges in the intake passages - but not too much or you can break through, but this can be fixed if you do. I used an inside mike and basically equalized all the pushrod bulges to the narrowest port. The intake ports can be gasket matched to the larger RA IV and then taper blend the larger port opening down into the port about 1".

A 3-angle valve job will also help. But, most of the additional flow comes from the valve throats and blending and you have to know what you are doing in this area.


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## soberjoe (Nov 28, 2016)

Thanks man 


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## Jim K (Nov 17, 2020)

soberjoe said:


> Hey Jim - I was just speaking with the guy working on my heads, and he was curious if you had any other cross-sectionals available - a lateral view into the back half of the head, or anything showing how much room to the water jackets?
> We are, I think, at the point of 'good enough' for my application - rather than risk a costly oops. Just the same, he wants to be sure that he isn't leaving too much on the table if you know what I mean.
> 
> I ended up getting the QFT VS-780-SS and he has done some tweaking to it to bring out the best that it offers. We are now simply awaiting the arrival of my rotating assembly and top-end kit from Butler.
> ...


Hey Joe,
These pages are the only other thing I could find around porting. As Pontiac Jim said... Time, usage and rust have probably diminished the thickness of any water jackets. The only way to check them out is by portable ultra sound. We used them a lot in the pipeline industry to check corrosion depths. (had to show them as attachments.. Wouldn't let me insert pictures.)


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## soberjoe (Nov 28, 2016)

Jim K said:


> Hey Joe,
> These pages are the only other thing I could find around porting. As Pontiac Jim said... Time, usage and rust have probably diminished the thickness of any water jackets. The only way to check them out is by portable ultra sound. We used them a lot in the pipeline industry to check corrosion depths. (had to show them as attachments.. Wouldn't let me insert pictures.)


Thank you Jim 


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