I'm in the process of replacing the A/C compressor on my 94 Z/28 with 6 speed. The parts house listings show a different part number for the manaul and automatic transmission cars and NAPA's website shows the clutch being a 5" diameter for the auto car and 4.25" for the manual car.

Anybody aware why the clutch is larger for the auto car? Larger clutch versus the manual car would mean the compressor turns faster for the manual trans car. The compressor itself is supposed to be the same part number. I haven't seen anything indicating the balancer is a different size which would drive the compressor at a different speed and people monkey around with ratios on crankshaft speed to accessory speed by switching to underdrive pullies all the time and that seems to work fine.

 

I knew that different years had different compressor pulley sizes, but was not aware it was divided by transmission choice. The GM parts book only bears out that the a/c pulley size changed in the 1994 model year (for both manual and auto). The crank pulley size never changed.