You may be able to check with some transmission places about identifying the 5spd you have. Toyota was notorious for not marking them for general public. They should be able to tell you what the final drive ratio would be. Most are a 1.0 or maybe even .77 but thats highly unlikely for an early model 5spd. I love the bottom end the 4:10's gave me but I could really go for a 6spd with this combo to get the top end I'd like. But thats more money and BS than I want to deal with right now.

As far the speedo you'll have to deal with the transmission shops. Usually its a simple swap of the drive gear for the cable. I'm not real up on what can be done with the toyotas but I need to check into it soon myself. Mine seems to be off by about 8 - 10mph. It was that way before especially with the 13" wires.

Jeff, I found these sites and they seem pretty interesting if not helpful.

http://www.gaugeguys.com/speedcorrect.htm
http://www.gaugeguys.com/ratiotest.htm