Driveshaft question

Your transmission crossmember and mount will work right back, same bolts and all. One thing you need to check on the proposed 727, is to see if it has the mount on the bottom of the tailshaft housing for shift linkage for console floor shift cars. If your car is a column shift, no need to even worry about it. The difference in tailshaft housings on small block 727's depends on whether it was a truck/van trans or a car trans. Car housings will have the little mounts cast into the bottom and truck housings will. Snap ring access plates are on the side of truck tailhousings and on the bottom of car housings.