Any Buick 231 gurus here?

[fesser]

I have a 231 v6 in a 45 Ford GPW (flat fender Jeep). I think the engine is a 1976. I'm replacing it with a 1980 231. I know that the heads are somewhat different (intakes won't interchange) but don't know the details. Question is, will my existing exhaust system still bolt up without being modified. I am currently running stock cast Buick manifolds. I am hoping not to have to modify the exhaust I have. I have found websites that say the exhaust manifolds interchange and have also heard that they are different. Thanks.

 

[76zimmer]

I think the changes were made when they went from odd fire to even fire...late in 1977, more head changes were made in 79, what they were I don't know???

 

[bushmaster]

i did this swap a 75 to a 81 and i used the same headers on both, the later engine does have better heads-larger valves and better flow