Welcome to CHR!

Love the look of the 72 – handsome car for sure.
Well there’s bad news and not a lot of good news about the 1972 version of the 350 Buick engine. If in fact you have a true Buick engine and not a GM “corporate” 350 (AKA Chevy 350), the engine had pretty pathetic heads from the factory and they were unique to Buick. There’s not a lot that can be done with the Buick 350 unless you want to spend a lot of cash and the chances of finding boneyard heads that can be reworked are slim to none. I know of no aftermarket heads for the 350 Buick. There are a few aftermarket camshafts and assorted aftermarket intake manifolds for 350 Buick on e-bay that may be worth a look.

If you want to more add power and stay Buick, the 455 will bolt in with a bit of work.

There may be some hard core Buick guys here that know a lot more about this – but as I recall, the only interchangeable parts between 350 Buick, Olds, Pontiac and Chevy are distributor caps and carbs..

Best,
Glenn