What engine and car they were designed to fit.
block hugger headers
yes
No.
No.
The headers would be the same anyway, so you can order headers for the 83 and be all set.
no
No. The Pontiac headers will not bolt up to the Chevy small block.
Don't buy slip fit headers. If you are going to spend the money, spend it right. Slip fit will give you a big headache, no matter who installs them. They will leak like a sive and drive you crazy. I recommend that you get hooker headers.
Pontiac 455 headers generally do not fit a Buick 455 due to differences in the engine's exhaust port locations and bolt patterns. While both engines are part of the General Motors family and share some similarities, the specific design and dimensions of the exhaust manifolds and headers vary. If you're looking to upgrade to headers for a Buick 455, it's best to choose headers specifically designed for that engine to ensure proper fit and performance.
No, the blocks are different.
Yes if its stock no headers?
yes