I have a Tremec TKO with a 5 speed(.83 5th gear ratio). I cruise 50mph @ 2000rpms.........60mph @ 2300rpms....and 70mph @ 2600rpms with 3.55 gears and 25.89" tall tires. Get a 5 speed, they are lots of fun. The normal .68 5th gear ratio, you could probably go with 3:73's or 4:11's. The .83 ratio vs the .68 ratio is about 500rev rpms faster.

______________________________________
www.spalisautodetailing.com
347 Stroker/XE284H(284/296 dur, 240/246 dur @ .050), BG 650 VS Speed Demon, Ported Victor Jr intake, Jack Roush World Jr Heads (ported from 180cc to 195cc)(upgraded to 2.02/1.60 valves) 260cfm/190cfm @ .550 lift, 11:1 comp... 450-475HP