79 vs 87 internals

[ktbundy]

Do the 79 and 87 engines share the same internals(pistons, crank, cam etc)?? And are the heads similar(flow, valve sizes, etc)also? I'm interested in building up a 79 engine but wnated to make sure it's a good base. Thanks in advance.
Tom

 

[fc227]

Well, I build a 1979 block and I am running low 13's - high 12's. But I am using the 8445 heads that are fully ported and polished and an after market Comp cam "206" the 252 series.

Check out my web site

 

[turbofish38]

Well I far as I know the cranks and rods are and the pistons usually are although if you look in a parts book they sometimes show different numbers. Camshafts are interchangable. Cylinder heads are different but the general opinion seems to be the ports are the same. I have noticied that as GM changed the blocks about every other year they made improvements in the durability. If you look at the valley and main webs of an 87 you can see they are much beefier than those of an earlier block. If you are building an engine for all out racing the 87 "109" block is what you would want. Same goes on the cylinder heads. Each casting number change brought saw more material added.

Eric Fisher

 

[b4black]

Is this for a 87 SFI motor, or a 79 carb/turbo motor?

 

[ktbundy]

Actually neither. I'm going to convert it to propane. I was curious as to how good the early motors were. I would like to build a stout engine without getting too insane with the boost. The car is in terrible shape, but I figured I could find another donor body anyway. I would more than likely be looking for an aftermarket 4bbl intake for the propane. Do any other engines use a similar intake to the 3.8? When I say similar I mean something that will bolt up. Thanks.
Tom

 

[b4black]

Unless you going will be wicked fast, the 79 motor will be great. It can use all the same internal parts as the 87.

The Buick 3.8 and 4.1 are the same engine except for the bore and pistons. The 4.1 had a factory aluminum 4-barrel. There are plenty of aftermarket four-barrel intakes as well- Edlebrock, Weiand, Holley and more. Check ebay. Just makes sure they are for the high ports heads (1979 and later).

 

[ktbundy]

Thanks for the info. That gives me a bit of an idea for my intake manifold. I can't see myself going too crazy with this set-up, so it sounds like the 79 motor should work fine.
Tom