This may be a dumb question but its always better to ask and be sure.
I have a Pontiac 350, if I want to make it into a 400, what all would have to be done to make the crank n all fit? Are the crank bearings the same size as the 350 crank?
Any clearancing need to be done?
This is my first pontiac build I have always done Chevys so forgive me in my lack of knowledge.

I bet its cheaper and easier to buy a 400 block....or used 400 engine.

Bore the block bigger and get new pistons and rings and you have a 400 short block. Same crank/same stroke/same bearings.

Can a 350 block be bored out that much? Even if it can it will still say "350" on the block. Like Bjorn said, cheaper and easier to find a used 400.

So a 350 crank is the same stroke as a 400 crank?
How much bore are we talking? Seems like a lot.

Just found some good info. Looks like I'm going to try n sell my 350 motor and find a 400 or 455.
Can't bore the 350 to the 400!
Thanks to all that replied.

Maybe I'll go with a sbc to make it easy and cheaper

and make your car worth 5000 less... you already have the stuff to bolt in a 400. sbc weighs almost as much too.

You were joking about the SBC right?

Yeah, I want to keep it pontiac.
It was a joke.
I still have to see what heads I have on the 350 in the car.
And see if they are worth using on a 400 build

sorry, I guess I'm too used to being around people who see nothing wrong with chevy powered Pontiacs. Good luck with your build.

Time to find new friends? Sorry, kidding. Didn't they assemble some Pontiacs in Canada with sbc's? I have a '68 that was exported to Canada so maintained its Pontiac driveline.

The 350 and the 400 both have a 3.75" crankshaft, same stroke. The bore of a 350 is 3.875" and the 400 bore is 4.120" You could just rebuild the 350 nothing wrong with one of those, but if you're set on a 400 your going to have to buy a replacement for the 350.