# Roller Cam or Flat Tappet in a 400



## Dean Benson (Dec 22, 2013)

I'd like a camshaft recommendation.

This is for a 64 Lemans convertible, it will be a street only cruiser, driven to work a few days a week on the interstate, local cruises/car shows. 2.93 posi, M20, Pypes 2.5, R/A manifolds, 65 Tri-power, power brakes, full roller rockers (ratio depends on what you recommend, I have 1.5s now). I want the engine to be all done by 5500 RPM and run on 89. We have 91 octane here now but...

I just bought a fresh never fired 75 400. +.040 TRW, XE262, recon stock rods w/ARP bolts, balanced, pistons are .015 in the hole (I've only measured one so far). It has fresh 6X-8 with no port work, stainless valves 1.77 exh. 

I plan to ditch the 6X-8 and use my other fresh 6X-4's, they have some heavy bowl work done and are gasket matched. I plan to disassemble the engine and have the block decked and squared to about .005 down in the hole. I plan to mill the heads to achieve 9:1 static. 

I was leaning towards a XE268 cam or a voodoo 60902, 
Part Number: 10510702
•Advertised Duration (Int/Exh): 262/268 
•Duration @ .050 (Int/Exh): 219/227 
•Gross Valve Lift (Int/Exh): .468/.489 
•LSA/ICL: 112/108 
•Valve Lash (Int/Exh): Hyd/Hyd 
•RPM Range: 1300-5500 

Seems many folks don't like the XE because they slam the valve down vs voodoo that lets the valve down easier. I started looking hard a Sandoval Performance's website and reading more about hydraulic roller cams. Now I'm torn, confused and tired of thinking about it. 

I was looking at his L/C2 206/[email protected] 110 LSA or L/C3 214/[email protected] 108 LSA rollers or "the daily driver" 224/[email protected] on 108LSA

I see VooDoo makes a similar roller to their 60902 HFT.
Part Number: 20510710
•Advertised Duration (Int/Exh): 262/270 
•Duration @ .050 (Int/Exh): 211/219 
•Gross Valve Lift (Int/Exh): .507/.515 
•LSA/ICL: 112/106 
•Valve Lash (Int/Exh): Hyd/Hyd 
•RPM Range: 1400-5400 
•Includes: Cam Only
Previous Part Number: 60910

It seems that there are only positives with a HR, more torque, less wear, decent idle. Are there any draw backs to having a roller cam with the tri power? Will I see a big drop off in fuel economy with a high lift roller? I'd like to get at least 17 MPG if possible. 

So what would you do? Is there a good HR that will fit the bill for what I'm trying to do? Or will the roller kill my MPG, (the reason I chose 2.93 axle). Am I better with one of the HFT? Which one?

I do not want a max effort, squeeze every hp out engine. 

I've kind of steered away from the OEM grinds because of the low 9:1 compression. Should I just stick a 068 in and be done? I have a crower 60916 on the shelf but I don't think I have enough compression for it either. I've heard the Crower 60240 HFT works pretty good in a 9:1 400. 

Thanks for any recommendations and advice to help un-confuse me.

Dean


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## ALKYGTO (Mar 29, 2010)

IMO that roller cam is too large for what you want. With the 2.93 gear and low compression she will be lazy down low where you drive 99% of the time. You say you want it to be all done by 5000 rpm but if you go with the large cam you are moving the powerband up in the rpm range so you are effectively narrowing the powerband.

If you had more cubes I could see running something larger but with the 400 and 9:1 compression I'd stay with something on par with the 068. Use that famous Pontiac torque to move that freeway geared, low compression convertible.


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## PontiacJim (Dec 29, 2012)

Personal Opinion.

I think a roller cam/lifters are a bit pricey for an average street build. Neat to say you have it, but I feel really not needed. And what if you don't like the cam? Expensive guess.

Flat tappet cams are great for the street, but you will read all the fears about a cam lobe going flat, the cam being soft, or poor quality. Get a cam/lifters from a reputable manufacturer. If they were all that bad, it would not take long for "that" company to get a black eye and be out of business. Sometimes I doubt these claims per say, because there are many dealers/sellers who want you to buy their cam brand - so they blog about xxx cam that went bad and they would never buy another and once they bought xxx cam, they had no problems. Bad press is a great marketing tool. And with a flat tappet cam, you must use an oil with zinc in it or use a zinc additive to prevent cam /lifter wear. Roller cams are not as sensitive -so this is a positive for rollers.

Hydraulic cams are the best for no hassle adjustment -install cam/lifters, correctly lash them, and your done. Solid cams require a periodic check/adjustment of the valve lash. Us hardcore motorheads don't mind the periodic adjustments because they have a unique "clatter" sound that implies "race car." I selected a solid for my build. The solid also gives you a more aggressive cam for the same hydraulic grind. The ramps on the cam are ground differently to open the valve up faster. Slamming the valve open and closed? Isn't that what a cam does? I personally don't feel this is a problem unless you get into some big spring pressures, but then you would not be really using this for a street car, and then you would go roller.

Once you know your actual compression, then you can look around for a cam grind -there are 100 different ones. The things to consider are indeed your compression. Then the RPM range you want to spin the engine and where you want your power band to be. Next is your rear gear ratio, transmission/torque converter stall, and even the weight of the car.

Pontiac knew what to do when they built their engines. They did not build them for high revs. They were built for broad torque and provided a good vacuum to run power brakes. The RPM range was aimed at daily drivers. 

You do not have to do a lot of modifications to get a great running street car & still get reasonable gas mileage. I personally don't think the XE cams on a 110 LSA are good for 9 to 1 and up compressions, although no doubt they are used. I feel they are best suited for under 9 to 1 as they build a higher dynamic compression to work with the under 9 to 1 compressions. Use this on 9 and over and you may have an engine that pings/spark knocks unless you use top grade gas or an additive. These cams seem to have a narrower power band, and drop off on power like a stone at whatever peak RPM they are intended for. But they do pull like a freight train with lower compressions. 

The cam you see advertised needing higher compression, higher stall converters/4-speeds, 3.55 gears or better are those typically having 114 LSA or more. Why? Because they have more intake/exhaust opening/closing overlap and bleed off some of that higher compression at lower RPM's, but gain it right back at the mid to upper RPM's. You would not want to bleed off any compression on an engine with 9 to 1 or lower. These cams can also be a little "sluggish" on the bottom end so on the street, you might not be too impressed with the lack of get-up-and-go at lower RPM's. Mid-range and up they would however rip your head off -thus you need the slightly higher stall converter and taller gearing to get your engine up the usable RPM range of the cam. This is basically what Pontiac used on the GTO's. These also give a broader torque/HP range and good vacuum.

So, my opinion, the 112LSA cam is just right for 9 to 1 compression if you go aftermarket.(I went with a Crower with the 112LSA) Then you want to select a cam duration number to match your RPM range. Very easy to get caught up in "bragging rights" and over cam on these numbers. Duration wise, probably 260-270 intake, 270-280 exhaust for street manners. Factory Pontiac lift on the valves were .406" with several grinds getting only .374" on the intake and .406" on the exhaust. Pontiac heads flow good at lower lifts, so I would not get too crazy for the street and put it somewhere around .450" max. Now here you could play around with lift. A .406" lift uses 1.5 rockers. Install a 1.65 rocker and you now get .446" lift. The 1.65's will also open the valve quicker which will act like a few more degrees of duration. If the engine responds to the 1.65's then keep them. If it doesn't seem as good, go back to the 1.5's - not all engines will respond favorably to more lift. The use of 1.65's sometimes require a little grinding on the head where the pushrod goes through -you open it up a little so the pushrod does not hit the head. It should not be a problem for under .500" lift, but while at the machinist, I'd have it done just to be safe.

The 1965 factory cam was the 066. 273 In duration, 282 Ex duration, .406" lift, 55 degrees of cam overlap. The 067 cam was 273 In/289 Ex, .406" lift, 54 degrees overlap. The 068 cam was 288 In/302 Ex, .406" lift, 63 degrees overlap. Lift stays the same, exhaust gets more duration to compensate for the restricted exhaust flow. With these 3 factory cams, I think the 068 cam would be the biggest factory cam I would go with, but gas mileage will be down. It may be too much for the 9.0 compression and be a dog at lower RPM's. I like the 067 cam as a better choice & it is going to be smoother with its lowered overlap -should get good gas mileage too. (Had a '67 GTO with this cam: lots of power & upwards of 20 MPG @ 55MPH back then with 4sp & 3.08's) And of course the 066 is good as well.

Invest your money in a good 3 angle valve job & a good dual exhaust system. -this is where you will get big improvements with a Pontiac engine.

There is no "one fits all" cam. Sometimes it is trial and error. There are "safe" cams and others that may not quite work as intended. Many of the cam grinders and/or Pontiac engine builders have a cam data sheet you can fill out with your car's info and they will recommend a cam for you. They know what they are doing. You can also ask them a question on a cam you think would work and they will let you know as well.

That's my opinion ('cause I'm no expert) and I'm sticking to it.:thumbsup:

I think *geeteeohguy* has the 068 in his lowered compression GTO, so maybe he has some input here as well.


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## BearGFR (Aug 25, 2008)

Ok, I'll play 
Advantages of a (carefully chosen) roller:
Less worry about wiped cam lobes due to no/insufficient ZDDP in the oil and/or improper break in.
Steeper opening/closing ramps mean that you can get the benefits of longer duration without the drawbacks of significantly increased overlap.
Solid roller cams have higher rpm potential.
Less parasitic loss due to friction.

Advantages of a (carefully chosen) flat tappet cam.
Less expensive.
No chance of a roller coming apart and taking the engine with it.

Disadvantages of a roller.
More expensive.
Hydraulic roller lifters are usually heavier (more valve train mass)
Risk of "bad things" happening if a roller fails.

Disadvantages of a flat tappet.
Break in procedure and proper oil (ZDDP) very critical.
Getting harder and harder to find high quality parts.
Longer duration means more overlap (negative effect on idle and vacuum)
More parasitic loss due to friction.

In short, it's possible to build a stout Pontiac using either and there are advantages and disadvantages to both.

I chose to build my engine with a solid roller system MAINLY because it allowed me to get the valve timings I wanted without having to suffer the effects of significantly increased overlap. My car idles with some attitude but it's not overly obnoxious, and it still makes 13-14 inches of idle vacuum. I bought good parts and did the job right, including putting in oiling restrictors in the lifter bore oil passages. I also went with good springs, titanium spring retainers, and full roller rockers. It was expensive, but it was what I wanted and I understood why I was doing what I did.

It'd be a lie if I said that my way "was the only way to build an engine", because it's certainly not.

To pick a cam, start with how and where you plan to use the car, how it's geared, what kind of transmission it has and honestly where it's going to be spending most of its time, RPM-wise. Pick a cam that has duration, lift, and lobe separation specs that are optimum for those conditions. (Having some sort of engine modeling software is very helpful here. I used Performance Trends Engine Analyzer Plus). When you're running the simulations, pay attention to the effect that lobe separation and type (roller or flat) both have on rpm range and idle vacuum. You should start to see "patterns" emerge that tend to steer you towards what's right for you.

Bear


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## geeteeohguy (Feb 2, 2008)

I am running a 9.3:1 original 400 in my '67 GTO convertible. Original distributor and carb. Using a Melling 068 spec cam (it's been in there over 20 years). With a very lazy 2.56 rear gear and a TH400, the car does fine. Good power from idle to 5200 rpm, but I never rev it that high. It's a great cam for a street driven car, and good on fuel mileage, too. Roller rockers are nice, and come recommended for a high performance (450 HP on up) engine, but are overkill for a basically stock street driven car. I've put about 70,000 trouble free miles on the 068 cam since I installed it.


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## Dean Benson (Dec 22, 2013)

Thanks for all the advice. I appreciate it. I just found out today, the machinist I was hoping to use is retiring. I've been waiting a few months to bring him my parts and start/finish this build. I was hoping he could help me sort this all out. He recommended XE274 but ground on a 112. I think this may be a little big for my combo, he didn't know my rear gear ratio (2.93), when we were talking.

Anyhow. I think we've narrowed it down to a 112 LSA.

I have a used cam (maybe 10k miles on it) out of my 350, it's a melling 214/224 442 465 on 112, this is real close to a summit 2801, and similar to the 068 212/225 but with more lift. This may work. 

I keep going back to the voodoo 60902 219/227 .468/.489 on 112. Lunati recommends it as their Tri-Power cam.

or the voodoo roller 60910 211/219 .507/.515 on 112

Other folks have recommended the Crower HFT 60240 210/221 422/446 on 112

This is going a 9:1, +.040, 400, with 87cc ish 6X-4's, R/A manifolds and 2.5 Pypes fed by a Tri-Power. 4 speed power brakes.

Is there a free engine simulator software package I can down load? I've been playing with CamQuest, but they only have their comp cams to choose from, and the engine parameters mainly revolve around SBC specs. 

The roller may just be a waste of money at this point. Nice to say I have it, but 90% of folks won't even know what it is. 

Thanks again for the help. 

Are any of the cams above jumping out at you? For this combo? Most of these cams are all similar in specs, designed for higher compression. The asymmetric lobes of the voodoo should help with my 9:1 SCR.


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## geeteeohguy (Feb 2, 2008)

With your 2.93 rear and a stick, you want to make power right off idle and in the low end. Your camshaft choice should reflect that. (mild or close to stock). A big cam that ups the power in the high end will make your car a poor performer with those rear gears. A stock cam, it will run pretty well, though a bit soft out of the hole. (3.08 is as low as Pontiac went with stick cars for this reason).


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## PontiacJim (Dec 29, 2012)

I feel the 2.93 posi may be a stumbling block. You are going to have to run short tires, ie stock 26" diameter. If you go larger, you effectively lower the 2.93's even more. You may have a problem if you select a cam that requires a higher than stock idle because you won't be able to pull the car down below 10 MPH without having to push in the clutch because the car is "bucking". I had this experience with my car as I went with tall tires, I think I figured them to be 3.23's, and had a higher idle -so be aware of this in your cam selections.

Stock Pontiac heads are said not to produce much extra benefits go too big on the lift. You did some bowl work/port match which should allow you more flow numbers at higher lifts. Did the same with my heads but, I too was not sure what cam to use because each cam is truly car/engine build specific and what may work well for one guy might be a dog in another's. Some of these guys select a cam and then fine tune that by swapping a ton of parts from carb to gears to get it dialed in -then they say it is the greatest cam ever. Was it the cam, or all the parts matching?

For that reason, I still feel a roller is not the best first choice until you get a cam that you feel is best for your car. You can try a flat tappet cam, not care for it, and later try another grind. Little bit cheaper. Find one you like, then go roller if you feel you want to add one.

I feel the 112 LSA is still a good choice for 9 to 1 compression. Now looking at your cam choice, because you have it, I would honestly try the Melling cam first. Is it a little small? Not necessarily. Smaller cams build more torque. Torque is exactly what you want with those 2.93 gears. Your heads will do the extra flowing without the need for a bigger cam. 

But, here is what I see as an advantage and what I too am doing in my cam choice with my 455CI 9 to 1 compression engine, 112 LSA, 284/288 duration. Got a solid cam that will give me a very modest .455" net lift at the intake valve. Not very big by Chevy standards or anyone else's that you read about, right?. The lift is based on 1.5 ratio rockers, and so is your Melling cam. Your Melling cam gives you .442" In & .465" Ex. using the 1.5 rockers. If you switch up and go with the 1.65 Pontiac rockers, you now get .486" In & .511" Ex. The 1.65's also open the valves quicker which effectively gives you about an additional 3 degrees more duration. So you can experiment here with lift and see how it changes the engine characteristics. You can also experiment with advancing or retarding the cam to slightly change the powerband -making sure you have valve to piston clearance which you should do anyway for your engine build.

If you try the 1.65's, you want to make sure you elongate the pushrod holes in the head so the pushrod does not hit it at full up travel. Make sure you have springs & retainers to match the .511" lift and that the valve spring does not go into coil bind. I set my heads up to handle a good .550" or so lift and did the pushrod hole elongation. Also know I have the valve to piston clearances.

As another option you could also try the Rhoads lifters which will effectively reduce lift and duration below their lifter pump up of 2,500-3000 RPM (depending on oil weight). Click on this link to go to their site: Rhoads Lifters. This allows you to use a bigger cam, ie more duration and lift over the Melling cam (like the XE 274 on 112LSA), but the lifters make the cam act more like a stocker cam until it gets up in RPM's and the lifters pump up and the cam comes on at full lift/duration. Improves engine vacuum as well. I used these on my brother's 360 build and they do do their job. It is said they clatter a little like solid lifters, but if they do, I could not really hear it over the exhaust tone.

Cam selection can be perplexing. No one cam does it all. You want the best cam for your engine, but what is it? Honestly, I can't say, even in my pick of cam for my engine. Believe me, I read a ton of blogs, forums, "how-to's", books, cam technology, head flow, and everything in between. Does it mean I picked the "best" cam. Nope. I may have a dud on my hands, who knows. It simply boiled down to just picking a cam I felt OK with and bought it. I'll know more once it hits the road.:thumbsup:


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## geeteeohguy (Feb 2, 2008)

What Jim said, and what I tried to say. Selecting a cam is dependent on what 'combo' you are running. With a stickshift, aggressive high lift, long duration cams work well with stiff gears (3.55-.433) and headers. With a stickshift and a lazy rear gear (2.93-3.23) you want a much more mild cam, one that will produce the low end torque to let the car move out without surging, bucking, or lugging. You need an engine to run strong and smooth at low to mid rpms, not a high strung, low torque, high revving engine. With your 2.93 rear gear, an 068 grind and stock 1.5 rockers would be the most streetable choice. If you want to run a bigger, badder camshaft, you need to swap rears for at least a 3.36 ratio. BTDT................


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## ALKYGTO (Mar 29, 2010)

ALKYGTO said:


> IMO that roller cam is too large for what you want. With the 2.93 gear and low compression she will be lazy down low where you drive 99% of the time. You say you want it to be all done by 5000 rpm but if you go with the large cam you are moving the powerband up in the rpm range so you are effectively narrowing the powerband.
> 
> If you had more cubes I could see running something larger but *with the 400 and 9:1 compression I'd stay with something on par with the 068. Use that famous Pontiac torque to move that freeway geared, low compression convertible*.


And, after_ aaaaaallllll_ that, exactly what the "Chevy guy" said in the first response. :smilielol5: Sorry guys, I had too. :boxing_smiley: :bannana:


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## PontiacJim (Dec 29, 2012)

ALKYGTO said:


> And, after_ aaaaaallllll_ that, exactly what the "Chevy guy" said in the first response. :smilielol5: Sorry guys, I had too. :boxing_smiley: :bannana:


You're not a Chevy guy, you're an alternative engine styled Pontiac guy - I've already figured that out!:smilielol5:


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## Dean Benson (Dec 22, 2013)

*thick skull finally softening up....*

Thanks again. I think it's starting to settle into my head. Keep the duration smaller with the 2.93 axle. The roller cam is out.

The situation you are describing PontiacJim with too large of cam and a high idle is one of the problems in my 74 GTO with 350/4speed 230/230 480/480 cam and 3.08. It is a pain in a parade, damn near wears my left leg out, I'm still trying to find time to swap that cam in that car to the XE256, like we discussed back in Aug. Spring is almost here, I need to get in the shop....

Back to this 400 build.

I'm narrowing it down to the following:

My Melling 214/224 442 465 on 112 It's sitting in a box on the shelf
XE262 218/224 462 470 on 110 It's new and installed in the shortblock

both are similar to the 068
068 212/225 408 407 on 115 

I think the melling is the right choice. I can keep or sell the XE262. My heads are elongated for 1.65 rockers and set up for .510 lift. I've to do some measuring but I imagine they can handle .511 lift. The bowls are opened up, the intake and exhaust are gasket matched. I'll probably start with the 1.5 roller rockers. I already have them. 

So I guess I'm ready to have this block decked, it's a fresh engine I bought from a guy needing cash, I took it apart to verify what he said it was. What's a good number to go to for deck height? .005 down in the hole? .000 down? I want to get good quench and hopefully not have detonation and running hot issues. 

Is 9:1 the number to shoot for? These are 6X-4s at 93cc now, I was going to take them down .030 or so to 86-87cc. 

Thanks again guys for helping.


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## PontiacJim (Dec 29, 2012)

Sounds like a plan with the cam.

Yes, 9 to 1 compression is what I feel is a good number to shoot for on an iron head build. 

The quench area number to shoot for is typically .040" and this can be a little more in my opinion -based on my machinist's explanation. Typically the pistons are .020 down in the hole, but really have to be measured. You will have to install the crank/bearings/rod/piston to verify. My machinist did this on all 8 cyls as there can be/and was some slight differences. So on average, most of mine were .020". You can't guess on this one, so you have to get that number first before you do any head milling. I think the true reason to zero mill a block is to take advantage of the .040" head gaskets that are typical and readily available in most rebuild kits.

I am not a fan of zero decking the block. What if you go to rebuild the block next time and heaven forbid, the deck surface is warped? What are you going to mill to re-surface? Probably won't happen, but....... I used th Cometic .027" head gaskets. They are not cheap at about $100 each, but you are going to have to pay to have your deck milled, so not doing this makes it an easier cost to swallow. My .020" down in the hole pistons plus .027" gaskets give me a .047" quench. Everything expands with heat (more so with forged piston and nitrous) and parts can stretch a little, so that .047" will drop down a little and it should put me in a good safe range. Also, if you mill the deck, you drop the heads down. You have to take this into account along with any head milling so the intake surface is milled to match, otherwise you won't get the intake to bolt on. AND, you want to make sure your head bolts don't bottom out with everything being cut down. Not saying you cannot mill the block deck as many do. I just prefer not to.

So you need to get all your cc's from the area above the piston at TDC, the head gasket, the valve reliefs, and THEN see what your combustion chamber needs to be to get near the 9 to 1 compression ratio. I would not do any head milling until I knew all the block numbers first.:thumbsup:

Food for thought: If you zero deck a block, you leave no real deck surface above the piston to absorb heat. I would think that just that little .020" down in the hole would cause that upper part of the cylinder to act as a heat sink of sorts. If no deck to do this, I am thinking all your heat is then transferred directly to the head. This would make the head have to absorb more heat and transfer it to the water jacket area within the head. Pontiac's can have problems with cooling, as we know, but I wonder if this would aggravate the situation even more. Just thinking out loud here.


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## Dean Benson (Dec 22, 2013)

My short block is assembled, this was a fresh engine someone else built, I'm taking it apart to verify what it is and get what I want. It will just cost me a gasket kit (which I already had). 

The pistons are averaging .015 down, I've heard shoot for .005, TRW tech sheet says .008 if I remember correctly. Both of these leave a little for a clean up mill for a next build. 

I've read quite a bit on the forums about tight quench helping reduce detonation and helps the engine run cooler. Two issues I want to make sure I get right. 

I hadn't thought of running .027 cometics, mainly due to cost, but they would fix my quench issue, I've heard you need a really smooth surface for them to seal. I assume the factory deck finish is smooth enough and I'm sure we could get the heads smooth with a fine cleanup cut. 

Which way is better, just deck the block and use Fel-Pro or go with cometics?


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## PontiacJim (Dec 29, 2012)

"Which way is better, just deck the block and use Fel-Pro or go with cometics? "

This is the point where you get together with your favorite machinist and make that decision.:thumbsup:


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## geeteeohguy (Feb 2, 2008)

I too have never zero decked a Pontiac, mainly because I never heard of it when I did my own engines 30 years ago. But, there is nothing but raves about it on the other forum from respected racers and builders. It really does work. That said, I have PJ's mindset, too about 'using up' the block.....same reason I hate .060 overbores right off the bat for displacement. Once you remove the metal, you can't put it back. Not easily or cheaply, anyhow! My Sig Erson cammed 389 with a 4 speed and a 3.36 gear might possibly be able to run pump gas if I had zero decked it in 1981 when I built it....but who knows? My iron heads are right around 65cc, so my CR is pretty high. Still, it used to run on 94 octane leaded ok. Now that all I can get is 91 unleaded, not so much.


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## Bensjammin66 (May 12, 2009)

Lots of great info here! A call to Dave @ SD Performance is a good idea too. Tell him your goals and current gear, head, intake etc combo and he wont steer you wrong. I went with his "Stump Puller" roller in my KRE headed 468 build. Not cheap. 500hp with a nice idle and power brakes! What a concept after a decade of my old 60919 Crower flat.


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## BearGFR (Aug 25, 2008)

I didn't zero mine when I built it, mostly because in the initial configuration I needed every last shred of chamber volume I could get in order to be able to run those #722's on my 461. The concept is however very appealing to me personally, the only down-side being, as GeeTee said, "using up" the block. Another "detonation defense" advantage of doing it is that the pistons tend to protect the sharp edges of the cylinders at the top of the bores and help prevent detonation-inducing hot spots from forming there.

'Some day' I hope to be able to find someone who can repair my one cracked 722. They don't make as much power as the E-heads I'm running now do, but they're just cool. At some point in the future if I want to step this thing up some, I'll have to decide whether or not to commit to the E-heads and optimize compression for them instead of trying to have it both ways.

Bear


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## Dean Benson (Dec 22, 2013)

*One piece rear main*

I've got the new to me fresh never fired engine completely apart, I'm dropping it off tomorrow to have it decked. After talking to the machinist and reading countless forum posts. I'm going to zero deck, .015 cut on the left bank and .022 on the right bank. Then I'll work on the heads, I'm going to shoot for 8.9-9:1 compression.

I'd like to try the one piece rear main seal, but my crank has the serrations for the rope seal. Do I need to do anything to the crank to make accommodations for the seal? Has anyone had any good or bad luck with one.

Thanks
Dean


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## Chris-Austria (Dec 23, 2010)

We installed the one piece seal from BOP on Saturday. Easy to install and no leaks so far. I think that's a really good piece. I once read that the serrations can be polished a little if they are too thick but I can't remember how much should be left. My Eagle crank didn't need that.

We used the cylinder head gaskets from Butler, they seem to work very good as well and the quality is much better than Fel-Pro's in my opinion... about 4.2" bore instead of 4.3" and better water passages.

Thats how they look:


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## geeteeohguy (Feb 2, 2008)

Dean, the past 3 engines I've put Viton 2-piece seals in all have the serrations on the crankshaft. The key is, where the lip of the seal is. It can not ride on the serrations. Two of these engines had a pretty good safety margin, but the crank in my own 400 was very close...which made me nervous. Been 4 years and about 6000 miles, dry as a bone. If you are worried, or if the seal lip contacts the serrations, rather than trying to polish them, I would run a Best Gasket Graph-tite square rope seal. JMHO..........


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## Dean Benson (Dec 22, 2013)

Thanks for the info. That's good to hear, I have a two piece viton seal from Ames, I'll have to look to see if it's BOP or the other brand and test fit it with my crank when I get the block back. I was deliberating on buying the one piece seal. 

I dropped the block off this afternoon to get decked. I started going over this combo with the machinist and he doesn't like 112 LSA cams for the street, he thinks I'm better off with 110 with my rear ratio 2:93. 

I was about to order the voodoo 262 on 112 cam 60902. He thinks I should stick with the XE262 I already have. It's closer to the 068 duration wise but narrower LSA. Jim Lehart recommends the XE262 on most of his stockish low compression rebuilds. I guess I need to do a little more research, the engine will run with either cam. I just want to build the engine for better low end torque.


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## Dean Benson (Dec 22, 2013)

I guess I should also say, this is a chevy shop, he builds occasional Pontiac engines, he actually had 2 in the shop, but he wasn't sure what I was doing when I was looking for the 4 or 8 on the 6X heads for one of the 400s. He does quality work and he's just decking my block. So the 110 LSA may work great in SBC, but from what I'm reading now, the 112 is probably better in the Pontiac. ???


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## PontiacJim (Dec 29, 2012)

Dean Benson said:


> I guess I should also say, this is a chevy shop, he builds occasional Pontiac engines, he actually had 2 in the shop, but he wasn't sure what I was doing when I was looking for the 4 or 8 on the 6X heads for one of the 400s. He does quality work and he's just decking my block. So the 110 LSA may work great in SBC, but from what I'm reading now, the 112 is probably better in the Pontiac. ???


Well, in your original post you said your machinist recommended a 112LSA. I take it you found another machinist? This guy recommends the 110LSA. I hate when that happens as it simply confuses everything.:yesnod: I think it is really a coin toss. I don't claim to be an expert, but my concern would be with the 110LSA cam as from what I have read, the 110LSA cam builds more *dynamic compression* and this is why it works great on lower compression engines. On higher compression engines, this could be a problem that leads to detonation. Read this: COMP Cams® - Sorry... Pay attention to "Effects of Changing Lobe Separation Angle(LSA)". With your 9 to 1 compression, I still feel 112LSA_ might _work better.


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## Dean Benson (Dec 22, 2013)

*put this to bed*

Jim, Yes I had to switch machinist's, the one I waited 5 months to get into, decided to retire during his Christmas break. So I went to the local guy, who I'm tending to trust, he seems very thorough, clean shop, organized, busy, but willing to stop and discuss options with his customers. 

I talked to another Pontiac builder today who was helping me with the voodoo, he didn't realize already had the XE262, the voodoo 262 is a little longer duration and higher lift but the 112 will bleed off some of the dynamic compression and he thinks that these two cams act very similar in my combo. They are both modern versions of the 068, CVMS also recommends the XE262. I've just decided to put it together and run it with the XE262 once the block is back. I don't think there is that much difference between these two. I'm no expert but I've done too much reading and fretting about this. 

On rear main seal, I think I'm going to try the best gasket rope seal, the builder I talked to today really likes them, says they cut like a chocolate bar compared to the old rope seals of the past, and he hasn't had any leakers.

Thanks for all the help and advice. If it's turd, swapping cams to something else isn't the end of the world, and/or swapping rear ends/gears, but I want a freeway flyer for the 35 mile interstate trip to work each day. So I like the 2.93.


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## PontiacJim (Dec 29, 2012)

Dean,

Sounds like a plan. You don't want to over-think it, sometimes you just gotta jump and see where it leads. If you aren't happy with the cam, not too difficult to swap. If you nail it down and like it, then if you want you can at some point go roller with the same specs.

ALSO, please keep this post in mind when you do get your car up and driving again. It would be good to hear from you and let us know what you think of the cam choice given your engine's compression and rear gears -if it's a go or a no-go.:thumbsup:


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## geeteeohguy (Feb 2, 2008)

The 068 I'm running in my 9-ish to 1 400 works very well in my 2.56 geared '67 with TH400. The XE 262 cam with your combo would be a great choice. What CVMS recommends for your package works for me. BTW, I have been running a 108LSA cam in my '65 GTO 10.5-11-ish CR 389 for the past 34 years. It runs extremely well. Crappy idle, 10-12" vacuum, but great power all the way thru the band with the tripower, 4 speed, and 3.36 gears. It would be the wrong choice for a build like yours.


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