I recently blew my Buick 454 motor and I have a spare 350. I was wondering if the 350 turbo automatic that I had hooked up to my Buick 454 will just bolt on, or if I need some type of conversion or just a new transmission entirely.

P.s. Also I would like advice on a good manual transmission too because I would like to swap over when I have the money.

 

Buick, Old, Pontiac share a bolt pattern, but Chevrolet has a separate pattern. The BOP trans will bolt up to a Chevy, and the alignment pins match up, along with 4 of the 6 bolts. But the other two bolts don't line up. I've seen guys drill holes and mill the area flat on the trans to accept the other two bolts, and they can then fit.
A few BOP trans had dual patterns, and would also fit a Chevy, but not many. You can look at your trans and see if it has 8 bolt holes instead of 6, which would make it one of those rare trans.
speedway sells an adapter plate for $39 also to adapt your BOP trans to a Chevy engine.
Chevy-to-BOP Transmission Adapter Plate - Speedway Motors, America's Oldest Speed Shop