Hi everyone, I have the prospect of purchasing a 430 block. I have the idea of rebuilding an engine and leaving my original 400 engine as is. Can someone tell me if a 430 engine fits my 67 GS A body? As far as I know, the 400, 430 and 455 are the same blocks, but are the engine mounts all the same? According to the Internet, the 430 was only installed in B, C and E body?! Thanks for your advice Emmanuel
Externally all three interchange, so exchanging your 400 for the 430 is no problem. You're correct, there was a GM corporate-wide "rule" limiting intermediate size cars to ~400 cubic inches until 1970. So, prior to '70 only the big Buicks got the 430. For 1970 the limit was removed - Buick, Olds and Pontiac released 455 engines for the A body cars, Chevrolet the 454. Devon
As a guy who has a rebuilt 430s and 455s, I can tell you its a bit cheaper and easier to do a 455. The 430 piston choices suck... both are doable, but depending on your goals you might be better off waiting for a 455..
Good advice, Joe. Wasn't too bad when I bought 430 pistons last time...but I think that was 1990! I, too graduated from 430 to 455 after that; at the time it was simply to gain more displacement. Devon
Good to know! I actually plan to bore the block to 455. But sourcing parts for the 455 also seems to be difficult. TA aluminum heads and other parts will be a challenge these days. But I have time, my GS is running well at the moment and I have enough to do on my Ford project... If I can get the 430 cheaply, I will buy it, and if it is good, I will use it for the conversion and leave my 400 original. Emanuel
I know about a 430 in the Netherlands that will be overhauled in the next couple of months. Maybe the builder also knows about a 455 to overhaul, he just sold one the other day. This is the 430: And this is the fresh 430 that my mate bought from the engine builder, next week I will drop it into his 1973 Century Regal:
I dont know if there is actually enough meat in walls to bore a 430 all the way to a 455.......they are the same externally and drop in interchange from 400/430/455. Heads swap around......but i think the internal casting around the walls is different for all the motors.......so do some homework to see if a 430 can be bored .125
Good advice on boring. I remember, too, reading the 430 can go to .125, but probably not any more than that. Cylinder wall thickness testing will tell all. Devon
You're right! It would be quite risky and involve a different test. It would be better to get a 455. In addition, the price in the auction was so high that I couldn't keep up.
