I bought a newer oil pan for my 87. In great shape, used from vette2vette. I'm going to repaint the outside with engine black paint. It doesn't need it, but since I can, and it's easy, I will. As for the inside, should I do anything to clean/prep it?

Clean the entire pan with simple green and rinse with a hose.

The inside needs to be lightly oiled so it won't surface rust... it just looks ugly, too.

The outside, clean with laquer thinner and then paint. Use high-temp engine paint from a rattle can. Works surprisingly well. I would warm the paint and the pan... if you can put the pan into a slow oven, say, 100F, that will help a lot... the paint can be rested in a bowl of hot water before use.

Perfect advice!

Yea, what Bogus said. You can also use WD40 on the inside of the pan, they don't call it Water Displacement 40 for nothing. Spray it on a rag and wipe to keep it off the outside.

I use the "warming up the paint in the sink" technique all the time. 2-3 light coats with ample drying time are better that 1 heavy coat.