Does it have the stock 4 speed stuff in it or are you starting from scratch?
All the stock 4 speed stuff in the car can be reused if you turn the OD tranny's input bearing retainer down to fit the bellhousing. The tranny will just bolt it then with no need to change the bellhousing, z-bar, or any clutch parts.
This swap is super simple, it sounds like you're over complicating it.
The shifter and shift rods can be reused, but the 3/4 shift tab is flipped on the OD trannys, so you might need to modify that shift rod.
I have converted at least six cars over to 4 speeds so far, and just wrapped one up Friday.
