Hey everyone, I'm sure that this has been discussed many times but my searches have proved un successful. Can anyone tell me will 3.4 heads fit onto a 3.1 block out of a 96 Grand Am. FOr that matter could I just use the 3.4 upper intake? I've always planned on doing my 3800 SC swap, but as luck would have it, this 96 Grand AM GT fell into my lap. WHat are everyones thoughts on this motor.

It all depends on the years. All the Iron Head motors, the 2.8, 3.1, and 3.4 have the exact same heads. The Aluminum head motors, the 2.8, 3.1, and later models have totally different heads. The rule of thumb is that they're 2 different animals and you can't mix and match. Iron heads go with Iron heads and Aluminum heads go with Aluminum heads. People have made the mix and match work, but its more work.

If you use the aluminum heads, then you must use the 3400 / 3100 intake system with them. It has been swapped like that before, but like he said. Its more work.

Obviously the 3.4 heads flowed better out of the factory then the 2.8 ones, but didn't exeed the 3.1 heads by much.

quote Originally posted by Custom2M4: If you use the aluminum heads, then you must use the 3400 / 3100 intake system with them. It has been swapped like that before, but like he said. Its more work. Obviously the 3.4 heads flowed better out of the factory then the 2.8 ones, but didn't exeed the 3.1 heads by much.

Actually there are two different aluminum heads... there is the Generation 2 and Generation 3... Gen 2 heads are what you find on early 90's GPs and Cavaliers etc... Gen 3 are the later model heads (3100, 3400) that are far superior to the Gen 2 or Iron heads. But even then GM went to larger valves in about 2000 or so on the Gen 3 which was another boost.

The moral of the story is find out what the intake looks like and only work within the same generation of head. Top end swaps between Gen 2 and Gen 3 are possible as they both use DIS for ignition but the earlier 2.8, like the Fiero, uses a distributor and has no where for the crank sensor to be installed in the block and the Gen 2/3 intakes don't leave room for a distributor.

Hope that helps a little... its never just easy is it? Oh yeah to answer your question. If your intake says 3100 on the top then the anwer is yes the 3400 heads will go on it. The only real difference is valve size.

------------------

[This message has been edited by carbon (edited 12-23-2005).]

quote Originally posted by poncho_101: Hey everyone, I'm sure that this has been discussed many times but my searches have proved un successful. Can anyone tell me will 3.4 heads fit onto a 3.1 block out of a 96 Grand Am. FOr that matter could I just use the 3.4 upper intake? I've always planned on doing my 3800 SC swap, but as luck would have it, this 96 Grand AM GT fell into my lap. WHat are everyones thoughts on this motor.

yes. all 2.8, 3.1, 3.4 heads fit any other 2.8, 3.1, 3.4
now, to keep things simple, you want to stick to the style you already are using. (iron, alum gen II, alum gen III, and I think alum gen IV)
but, if they are differnt styles - the newer heads are the better heads - and you should take the whole intake system along with the newer heads.

quote Originally posted by Fastback 86: All the Iron Head motors, the 2.8, 3.1, and 3.4 have the exact same heads.

Not really. There are 2 versions of the cast iron heads. The regular heads and the H.O. heads. The H.O. heads have larger valves and better flow. The Fiero and F-body 2.8L, the minivan 3.1L, and the F-body 3.4L all use the same H.O. head. But the S-10 and numerous other cars that used the 2.8L in the late 70's thru mid 80's used the smaller valve heads.

If I recall you can switch between the iron heads and the Gen2 aluminum heads but you need to also change the pistons. This is because the head chamber sizes are different. So you could end up with very high compression or very low compression depending on which piston style and which head you use.

[This message has been edited by Oreif (edited 12-23-2005).]

The pistons, heads, and intake system are a matched set. For example, any of the aluminum heads only work with the intake and pistons that came with them, the iron heads only work with the intake and pistons that came with them. Using the aluminum head pistons with the iron heads will yield a completely unusably low compression ratio, I remember reading less than 7:1, and conversely using the iron head pistons with the aluminum heads yields CRs in the 14s or higher.

JazzMan