[BossHogg69]

There is no way in I would rebuild a 307 over buying a GM crate 350! I have not personally used one of those engines a vehicle of my own, but I helped my dad install two of them in two different vehicles and they both are still going strong (20 years later!) and were easy to swap. Decent power and reliable. You're basically just doing a remove & replace, everything should bolt right back up. Good call on the water pump & thermostat. New spark plugs, distributor cap, rotor and maybe plug wires if they are questionable.

Not so sure I'd replace the alternator unless you were having issues with it before. They are easy to get to with the engine in place if you need to replace it down the road.

You should look at getting an oil priming tool to pump oil through the engine before starting it up and follow proper break in procedures since that engine uses a flat tappet cam.