Stage 2 heads on production block

[Paul Lohr]

I am wondering about putting Stage 2 heads on a production 3.8 block. The Buick Power Source book may be suggesting that this can be done somewhat reasonably. The book says "...a Stage II head used with only four bolts on Stage I or older blocks has the same sealing concern and is horsepower limited, as discussed in regard to the Stage I head". That's all I've found so far in the book.

Here are the questions that perhaps someone can help with:

Is there a decent head gasket that will seal the Stage 2 heads to the production 3.8 block?

The valve arrangement is not the same on the production and Stage 2 heads so the production cam will not work. Could a Stage 2 cam be used in the production 3.8 block?

What about lifters...just use lifters from the 3.8 production block?

I realize the headers are probably expensive and difficult to find for Stage 2 heads. Has anyone attempted to rework a set of aftermarket headers to bolt up to Stage II heads?

Anything else I am missing here?

Thanks for any help,
Paul Lohr

 

[forcefed3.8's]

Sealing would be no different than using production style heads. Remember the Power Source book is from the 80's. Alot has happened since then. Cometics will work. A stage 2 cam will work in a production block. You will have to use production style lifters. If you go solid roller, you will need Crower shielded lifters. You will have to watch valve to cylinder clearance, as well as piston to valve clearance. For headers, production style headers would require extensive modifications. Better off starting from scratch. Both Stage 2 heads and ported GN1's or TA's will support enough HP to kill a stock block. No real point to doing the extra work to use the Stage 2's.

 

[turbofabricator]

Yes......they are a direct bolt on and will work, however definately NOT cost effective, even if you have heads for free. Cam, intake manifold, headers, new down pipe, rocker arms, push rods, pistons, wastegate, etc. TA heads would be a much better choice. Heck, a good set of ported irons will flow ALOT of air.

 

[charlief1]

Like Ken said, (glad to see you on old man) it's not practical. If you have some fab skills and the equipment you could use a set of Series II heads off a FWD engine along with the cam, but the intake and headers will have to be made. The heads bolt right on and it will give you more compression and better flowing heads. But again, you will have to make an intake from scratch as well as headers to do it.

 

[Paul Lohr]

Thank you very much for taking your time to help me, gentlemen.

Thanks for sharing your knowledge about the Stage 2 heads. I agree, in terms of money and time it makes sense to use heads from TA.

About the 3800 Series II FWD heads, will the 3800 intake manifold bolt up to the 3800 heads while on the production 3.8 block? Maybe I should start another thread on this topic because I have a series of questions.

Thanks guys,
Paul Lohr

 

[bison]

Thank you very much for taking your time to help me, gentlemen.

Thanks for sharing your knowledge about the Stage 2 heads. I agree, in terms of money and time it makes sense to use heads from TA.

About the 3800 Series II FWD heads, will the 3800 intake manifold bolt up to the 3800 heads while on the production 3.8 block? Maybe I should start another thread on this topic because I have a series of questions.

Thanks guys,
Paul Lohr

3800 heads will work on a 3800 block. The only thing they share with the LC2 is the rod bearings.

 

[KevinB]

3800 heads will work on a 3800 block. The only thing they share with the LC2 is the rod bearings.

And the main bearings too...they are skinnier and work with the chinese cranks well

 

[norbs]

If you need headers for stage 2 heads they can be made no problem, costs around $2500 or so I was getting some estimates, so its up to you if you want to go that route. The difference between heads is the stage 2 heads will produce the power at 1/2 the boost over other heads.

 

[Jerryl]

. . . . The difference between heads is the stage 2 heads will produce the power at 1/2 the boost over other heads.

Norbs,
Why is that? (Trying to learn.)

 

[norbs]

Because they are more more efficient , but low speed torque will be less they are designed for all out racing basically. But your better off to use them on a 4.1 The valves may hit a 3.8 bore.

 

[charlief1]

3800 heads will work on a 3800 block. The only thing they share with the LC2 is the rod bearings.

As is stated, the heads are about the only thing you can use. Everything else must be fabricated unfortunately.:frown:

Norbs,
Why is that? (Trying to learn.)

Heads Jerryl. Remove the restrictions and you get more flow.:biggrin:

 

[Nasty Wendy]

Once upon a time there was a production block being built with Stage 2 heads. I do not know how that story ended/ends though. I believe Mike Licht is the author of that fairy tale. It may be best to ask him.

 

[Jerryl]

. . . . Heads Jerryl. Remove the restrictions and you get more flow.:biggrin:

Because they are more more efficient , but low speed torque will be less they are designed for all out racing basically. But your better off to use them on a 4.1 The valves may hit a 3.8 bore.

Thanks guys!
For the sake of discussion and furthering my education;
Air Flow = HP, Boost = Mass Air, Flow+Mass Air = fun! :biggrin:

Fact is, the SII heads flow more air, period.
If the heads have the ability to flow more air, AND, the stock ported heads are a restriction, you will increase peak HP. (I get that part.)
If the set-up is unable to use the increased flow capability of the SII heads, the heads will not make a difference, correct?

So, if boost is constant, the Mass air for theoretical purposes stays the same (Ass-U-Ming other variables such as; Ambient, charge Temps, fuel, BP, cam are constant - it leaves only one variable, air flow.)

Having said that, typical VE on a set-up with ported irons is >85% and unless there is an increase in SCFM through the system, a set of heads that flows 200% of the ported irons “should” not increase HP in the +50% range.
Am I thinking about this correctly?

 

[norbs]

Thanks guys!
For the sake of discussion and furthering my education;
Air Flow = HP, Boost = Mass Air, Flow+Mass Air = fun! :biggrin:

Fact is, the SII heads flow more air, period.
If the heads have the ability to flow more air, AND, the stock ported heads are a restriction, you will increase peak HP. (I get that part.)
If the set-up is unable to use the increased flow capability of the SII heads, the heads will not make a difference, correct?

So, if boost is constant, the Mass air for theoretical purposes stays the same (Ass-U-Ming other variables such as; Ambient, charge Temps, fuel, BP, cam are constant - it leaves only one variable, air flow.)

Having said that, typical VE on a set-up with ported irons is >85% and unless there is an increase in SCFM through the system, a set of heads that flows 200% of the ported irons “should” not increase HP in the +50% range.
Am I thinking about this correctly?

Correct but your flow is limited by your turbo, I can;t say if you put stage 2 heads on and use a stock turbo that your going to double your hp, But put on a big ass turbo , you better bring a set of diapers with you if you turn up the boost.

 

[John Wilde]

Once upon a time there was a production block being built with Stage 2 heads. I do not know how that story ended/ends though. I believe Mike Licht is the author of that fairy tale. It may be best to ask him.

Shane owns that project now, maybe he will chime in.

 

[Reggie West]

With the difference in runner size and valves, I will bet you make max torque earlier in the rpm range ( yes the camshaft plays a big part in that) and you will make the same power at a lower boost level. Less restriction to flow.

 

[bison]

With the difference in runner size and valves, I will bet you make max torque earlier in the rpm range ( yes the camshaft plays a big part in that) and you will make the same power at a lower boost level. Less restriction to flow.

Not from what we've seen. Increasing runner volume is a setup for higher rpm. Which means increased duration and more overlap. All raise the peak torque. It's not typical to run a lot of runner volume on engines that operate under 5000rpm.

 

[charlief1]

Not from what we've seen. Increasing runner volume is a setup for higher rpm. Which means increased duration and more overlap. All raise the peak torque. It's not typical to run a lot of runner volume on engines that operate under 5000rpm.

There are exceptions to the rule but Brian is right here. The more room in the runners the more sluggish the air flow is at lower RPM levels.

 

[John Wilde]

I think is also depends on the way the Stage II are set up.
The $5k plus Chapman/Duttweiler (Castings only) would not do well on the street.
I would like to see how a set that was set up for a more mild combination would work.
Where is Mac in SD?

 

[norbs]

Some would have to a back to back comparison between heads on a stock block. But based on tuning my friends car running mid 9s@15 psi boost with a 274 motor, I don't think you can do that with production style heads or can you? His injector duty cycle is double mine with same injectors and turbo and same boost can someone explain that?