77 late L48 manual ac compressor pulley size?

[Ken S.]

my 1131078 AC compressor siezed (not false) and I decided to replace it and convert to R134. The original pulley size is 6". All the remanufactured and Delco replacements seem to have a 5" pulley and list 76 thru 82.
My calculations indicate that the compressor would run 15% faster with a shorter belt and the 5" pulley.
Do I need to remove the pulley and clutch from the old compressor or can I just install the new one with a shorter belt? Does anyone know when and if production changed to the 5" pulley and why?
Thanks for your help.

[Larry M.]

Re: 77 late L48 manual ac compressor pulley size?

Ken:

You can go either way. If you know (or believe) that the larger clutch is original to the car, then remove it, replace the bearing, and reinstall on the new/rebuilt compressor.

I had a 1978 Z/28 with factory air and A-6 compressor. Owned since new. The "compressor" also seized up one morning and I cut the belt to keep the car running to get to work. Turned out that the compressor was fine and the clutch just needed a new bearing. Replaced the bearing and was back in business.....no other repairs needed, not even a new compressor seal.

FWIW.......Larry