first time rear end swap

When I swapped to super stock springs I had to drill out the front hangers for the bigger bolts for the front eyelets. 5/8" I think. I later swapped to a new front shackle that offered a 1" drop. Easy swap. Unbolt the drive line and try to leave it in the transmission till your ready for the other so you done leak tranny fluid. Unbolt the front and rear hangers and take it out as a unit.