AC compressor on a 248 - best to run it off the crank or water pump pulley?

Curt Six

New member
I'm figuring out a Vintage Air system for my '41 Buick with a '49 248. What are the bearings like in that water pump? Do you see a problem with running a dual sheave water pump pulley and running the compressor off the pump? Or, alternatively, is it possible to separate the harmonic balancer from the crank pulley and make a dual sheave crank pulley? Running a dual sheave water pump pulley might be easier, but it seems like that might cause premature failure of the water pump.
Thanks for any input.


Active member
A/C compressor on a 248

I mounted the compressor on the original generator bracket. A couple of spacers to line the inner groove of the double groove pulley with the crank and water pump pulley. Mounted the alternator on top of the comp with a fabricated bracket and drive it off the outer groove of the comp pulley.

Several miles trouble free.



Active member
Drive it off the crank for sure. The water pump bearing will not take that kind of stress for long.


Take a look at my post, "my new 263", I had an adapter made to fit over the harmonic balancer which allowed the use of a SBC crank double pulley to drive my supercharger. It works well, I actually have to adapt a wider pulley to run larger belts but that probably wouldn't effect what you want to do.