What automatic overdrive are you running behind your Gen 1 small block?

[Onebean]

Kawabuggy and everyone else, thank you for the extremely informative responses. For now, I'm sticking with the tired 350. It is leaking from the front seal, so I'm going to fix that and keep on driving it. The truck has a 305, so there's little chance it will hurt the transmission. I'm going to start sticking away some money for a engine / trans swap next year. I've been drooling over that GM crate 350 that pumps out 357 HP and 407 ft. lbs. of torque. I'd love to pair that engine to 4L80E. That would be a fun combination. Again, thank you to everyone for your responses.

Onebean