Reverse Valve Body and Column Shift

I don't believe you have to change anything to just shift it except to eliminate the kickdown hardware. But the lack of safety features would be asking for trouble even if you are good at shifting a column. It would be illegal for sanctioned racing and simply not safe on the street if there is no reverse lock-out to prevent accidentally downshifting into reverse. Also, a "no braking" low gear valve body can cause problems on the street. No positive "stops" for each gear can also be an issue.

Will you be using proper weights on the converter or a B&M 360 LA flexplate for proper balance?

Early 904 and 727s had a smaller converter snout, so the spacer to fit the bigger 360 crank register was the proper thing to do. Early & late converters don't interchange in the transmission because of spline count.