Ok I just need some clarification on the difference between a 305/350.
I have two experienced people telling me two different things.
1. 305 and 350 are the same block, with a different Bore and the same stroke
2. 350 and 305 are different blocks, with different cranks and bore.

I pulled an engine that is supposedly a 350 and replaced it with another 350. However the flywheel would not fit on the new 350 (because the center whole was two small) My dad suggested that this may be a different because one block is a 2piece rear main, and the other is a one piece rear main.

Reason I want to know if because I was given the old block, however I am now uncertain weather it is a 350 or a 305... If it is a 305 I need to know if it is compatible with my 350 parts (I.e. will the 350 heads/crank fit properly in the 305 block) The whole engine is in really good shape, the guy I'm working with spun a rod bearing (but the crank and the bearings still look really good there is just a little play in them) But the guy has plenty of money and likes to spend it... so he bought a brand new 350 lol.

Thanks for any info in advanced