Vintage Air and Classic Auto Air both offer kits that put the A/C compressor in the stock location, allowing the use of stock length belts. One snag I found...Aluminum water pump housings place the thermostat housing slightly higher so the brackets to mount the compressor are slightly different. When ordering your kit make note of this. In my opinion, they should just default to the taller brackets so they fit every application. They may have a reason for having them different that I'm unaware of.
The compressor has four equally spaced mounting holes that allow the installer to clock the unit around to a favorable position and to aim the lines at 9:00, Noon or 3:00. For my car, I chose 9:00. I did the same here.
One snag that occurred in both installations. The mounting bolt that shares the bracket for the power steering pump
normally threads into a welded on nut at the back of the P/S pump bracket. The A/C bracket needs to lie there so the welded nut comes off.
To secure the bolt, you'll need to finger in a 3/8" nut in a cramped space. Edelbrock heads have a thicker face here that crowds the area more than stock or 440 Source heads. To allow fitment and full bolt thread contact. On this head below, you can see a cut in the corner on the lower LEFT of the picture.
The kit includes the thin nut plate to the right but it didn't look like it would be good enough compared to the thicker stock nut to the left.
The owner wanted to keep his stock fixed blade fan.
...THEN on a test drive after switching to the A/C pulleys, the faster fan speed made a whooooosh sound that he didn't like. That whoooosh is the trememdous airflow the fan provides using the smaller diameter pulley but at what cost? I am not 100% sure but I suspect that most if not all original A/C cars had fan clutches. The owner wants to swap to the clutch as part of the swap, that is also in the works.