what do you thank about a 305 with a twin turbo
You can get a 350 crate motor for what it will cost to do the turbo install, and it will make more HP and torque. Worse yet, the 305 has a weak bottom. I wouldn't do it. That said, if you're hell-bent on doing it, you'll need to have the 305 heads worked on to take advantage of the increased flow, or it will be pretty much a wasted effort. The 305 heads are lousy. With port and polish, and twin turbos, you might squeak 275 HP from the thing before burning a hole in the cast pistons. A bone stock 350 makes 290 and will last 100+ years.
the 305 won't handle the turbos. go with a 350 for a starting point.
Looking for a Used Pontiac in your area?
CarGurus has 13,666 nationwide Pontiac listings starting at $988.
Search Pontiac Questions