Welcome to the board
I have to agree with everyone as well. The 305 was not and is not a very desireable engine because for about the same price if not a little more you can get a 350 long block and have more power. I would look at a crate engine as everyone else has mentioned as well. GM has excellent warranties on most of their stock or mild replacement engines. Later on you can always upgrade items you didn't at that time. If you want a new complete engine with a new serpentine system (one belt system rather than 3) Pace Parts also has those ready to bolt in. Same item as above but with all new accesories as well. For the price you can't beat it. Plus a company that will actually stand behind their warranty for sure. Not some shop that could close down any time and you're out of luck.