Driveshaft length

So I can't put the car together yet cuz it's going out for blast and paint. But I'm trying to source a driveshaft. I'm putting in a 360 with 727 and 8.25 rear end on a 72 swinger. Anyone know of a resource I can look at to find my future driveshaft length?

Check this out. this is the shop i used to make my driveshaft. check out their measurment guide and see if it helps.

http://www.hudlowaxle.com/services/driveshafts/