last time I did mine, I took the alternators to a local autozone and they let me change them in the store so that I didn't have to actually rent the tool (impact gun). I ended up buying an impact from Harbor Freight if I have to do it again.
Chris
1985 Ford F250 XLT SuperCab
ZF5-42 swapped 460 hot fuel, factory AC.
Part way through 4WD swap.
1988 Suzuki Samurai -- Daily Driver
1968 Dodge Dart -- Project car
1957 Chevy 4400 Flat Bed -- Collector Project
1955 Buick Century -- Collector Cruiser