Manual Transmission Ideas.

That is a nice looking car.
Manual trans swap and CHEAP are usually not spoken in the same breath! People get lucky sometimes though. It helps to stumble upon a complete car so you can not only get every little bracket, rod and clip BUT to take them off so you know right where they belong on your own car.
If you want an overdrive.... There are 5 speed swaps that come with everything needed including a hydraulic clutch setup. Silver Sport Overdrives recently developed a cheaper, lighter duty 5 speed swap using a Borg Warner based T-5 5 speed, a transmission very similar to what was used in the 5.0 Mustangs, Z28s and Trans Ams of the 80s and early 90s. While this is not a bulletproof transmission, it will hold up to a lot of abuse if you are not drag racing with slicks.
Good luck. I'm thinking about a Tremec 5 speed for my car....and I never thought I'd stray from an automatic!