I was doing some reading on a couple camaro forums, and they were talking about swapping the upper end (heads on up) of a 3400 on to their 3.4s. It sounds like there are other modifications needed as well. Anyways, I was wondering if anyone here has done this to their 2.8, 3.1, or 3.4. If so pictures and info would be great!

Pistons. The combustion chamber volume is very different between iron heads and aluminum heads. You're better off swapping the entire engine.

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tho, I often ponder the possibilities of grinding out, carefully, the cumbustion areas on the alum heads. maybe do enough to get 11:1 compression.
what is the CC needed to be removed to get 11:1?

maybe we shoudl start with - what is the CC of iron heads & the CC of alum heads, and work from there?

the first concern would be to attempt to maintain the shape - just smooth/flare it out more.
would it make some sections to thin?

Yeah, they were saying that the pistons would have to be changed to avoid an extremely high compression ratio, like 13:1. The camaro forum said the iron heads have a compression chamber of 55cc and the aluminum heads have a compression chamber of 28cc. I was wondering the same thing about grinding or doing something to create more room. Maybe a thicker head gasket would help too.

[This message has been edited by crt454 (edited 02-02-2010).]

Why not do a 3500 upper end swap that has a 32cc head and flows better than a 3400 head, use the 3400 pistons and injector rails. A thinner head gasket too.

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The Iron head motors would benefit greatly from a gen 3 head and intake swap, but the other members are correct.

The compression would be way too far off requiring a piston change to correct the problem and if you are going to tear it down that far, you be miles ahead to just buy a 3400 engine.

As for you Lilchief you could do this swap very easily and get 40% more flow out of your intake and head set up by going to a gen 3 set of heads and intakes. The gen3 heads have the exact same combustion chamber volume as your TGP heads 28cc.

I had a 3.1 TGP I was going to build using a gen 3 top end, the only problem is the roller stuff.
The earlier GEN 2 blocks have no provisions for the roller lifter girdle in the lifter valley. There are two ways of solving this…

1 use your gen 2 flat tappet cam and lifters and abandon the roller stuff, you will still see a huge increase in HP over the gen 2 stuff.

The second option is to fabricate a girdle set up or notch the lifter and or bore to prevent the lifter from spinning.

I looked at both and for me the roller stuff was too good to leave on the table, this is what I came up with.

Weld several bungs in the lifter valley and use the stock gen 3 girdles. This is cheap and effective, the down side is that you need to pull the engine to weld on the block

This could be done without pulling the engine and just pulling the intakes by covering the rest of the valley with wet rags to soak the heat and prevent slag from entering the motor.

The stock lifter girdles are plastic and require very little mounting strength to hold, tacking some nuts to the valley would hold them without question.

If you are looking to get serious Comp cams sells a bridged set of roller lifters for this engine, but they are solid lifters and would require you buy a solid cam (this is the way I was going)

Great project by the way Lilchief, love to see what happen is you went gen 3 on the Top end.

Here is a short thread on the subject. 11.5:1 is doable on pump gas if the information posted is correct. I wouldn't do more than polish the combustion chamber in the aluminum head. If you want to reduce the compression look at the gasket oprions available in WOT tech or look into shaving a little off the pistons. http://60degreev6.com/forum...-w-3500-heads-t45554