1. yes
2. He was talking about the motor not the trans. A 4 bolt main bearing cap. You can use any 350. Every seller says their motor is a 4 bolt. Most are 2 bolt. No problem with 2 bolt
3. No
The 350's are cheap. Buy one in a running vehicle so you know it's good. $400-$600. Don't fall for all the guys who say it's been rebuilt. Sometimes that's a bad thing because they didn't know what the hell they were doing. Check it's oil, do a compression test on it and listen to it run with a muffler.
Keep your old 350 for all it's parts, brackets, etc. This will be a bolt in solution. Work on the old 350 at your leisure, and if lucky, you will learn something, fix it and sell it for what you paid for the replacement. Don't spend too much on it. $100 max.
