McLeod Racing Muscle Car 5 vs Tremec TKO600

[72 RS/SS]

I have a similar setup as my 72 RS/SS. 350 sbc with 400+hp and 3.73 posi out back. All I can say is switching from a Super T-10 4 spd. to a Tremec TKO 600 several years ago was one of the best improvements I've made in drivability and performance.
Hurst Driveline has the complete kit for your 68 with zero mods. Install everything in a weekend, be done and enjoy your ride.