If you mean the difference between the Pontiac 400 and 455....the differences are the bore size, the crank stroke length, and the main bearing journals. All are bigger on the 455. However, there is also a small block Chevy 400....which has nothing the same as the other two. The Pontiac 400 has a bore of 4.12, stroke 3.75 and 3" main journals. The 455 has a bore of 4.151, stroke of 4.21, and 3.25" main journals.
No. they are different head designs.
yes
Same block, should fir right in
600lbs
The firing order for a 1970-76 455 should be 18436572 Enjoy!
455
It had a 455.
Under the carburetor in the front.
A Buick 455 could be purchased from a dealer who specializes in vintage motors, or in this particular brand. Owner forums may also feature these for sale, as well as other specialist publications.
Because they oil the cam better than the crank. You need to have restricter plugs put in before you put the main bearing back in....
Not without serious modification, but anything is possible if you have enough money for a conversion.