TQ opinions/question

Upgrade the transmission it was designed for like 200hp and little torque of a factory 273. A shift kit is not going to make it stronger only change the shift points and find every weak link. If you are upgrading to a better transmission and a new style engine you can buy an off the shelf tc for that combo not the combo you removed. Find a good 904 from a 70’s Abody and never look back - after a rebuild that is. You don’t need crazy parts, just a good strong transmission.