A few notes from my install:
-Requires E/B body output shaft on an a body 4 speed
-mine did not require slotting and dropping the rear cross member. I ground a little clearance on the gear vendors cast aluminum adaptor, shifter mechanism adapter plate and put a few smalll clearance dents in the trans tunnel
-overdrive controller mounted in the glove
box
-shorter driveshaft required
-I’m running 3.91 gears, when OD is energized they are roughly a 3 to 1 ratio
