Pontiac 400/455 block

I've heard people say that the Pontiac block is the same size/block as an ?Oldsmobile 455. Are they right?...I have both and the olds looks bigger...Anyone know for sure, keeping me from measuring...

They are totally different blocks and none of the internal parts are the same. Best thing to do with it is sell it.

All Pontiac v-8 blocks are the same, from the 307 to the 350, to the 400 and 455.

But Tim is right, Pontiac and olds are not even close...

As an aside, Olds, Buick and Pontiac share the same engine/transmission mounting holes so the mating to a transmission isn't a problem. As previously said, nothing else is in common. Probably not even the motor mount position. I believe the Pontiac block is the most compact of the three, and Olds may well have the largest outside dimensions on the 455. As previously recommended, sell it and use the money to buy the correct motor. Ebay usually has pontiac 455 motors for sale in various stages. Recently a really built up motor w/ 4 bolt mains and SD rods, forged pistons, etc went for under $2K. Shipping costs can be high if its out of your immediate area.

I have a Pontiac 400 on a motor stand waiting to be rebuilt. I just had a friend say that he thought that the olds455 and pontiac400 had the same block size. I didnt believe it at all. I know that olds blocks are huge

Not the same for sure olds are a bigger motor as with buick's.there nice motor's shouldnt have a problem selling it..hope this help's but pontiacs are not even close to the old's & buick's, but both are desireable motor's not as like the pontiac
Travis williams @EdWilliams Machine boardman,oregon



travis williams