Some questions youu might want to ask are.

1. 2 or 4 bolt main.

2. How many miles on engine.

3.If it's had a rebuild, find out whats been done. What kind of pistons,cam,intake,carb,heads,lifters,valve springs. Has it been bored and if so how much.

4.what compression is it running. 8.5,9.0,etc.

These are some I would ask. I'm sure others will have more to add.