Engine options for 3-speed manual?

[deelowe]

I'm starting on my 1967 project truck and I've been considering keeping the 3-speed manual (on the tree), because you don't see many cars with this any more. What would my engine/transmission options be if I want to keep this setup? Also, what are some of the sacrifices I might have to make (such as: torque limitations, needing a tall first gear, top speed limitations etc..)?

I know a lot of people usually just opt for an automatic and I'm just curious about what I might be getting into. Should I just ditch it and get an auto?