57 three groove pulley, 2 different types??

[John Morris #23947]

I had two 57 Fleetwood 60 Special parts cars. Both had 3 groove pulleys. The pulleys were different. The one shown here, laying flat, is 3 and 1/8 inches deep. The other was about 1 and 1/2 or 2 inches deeper, with a longer "nose cone". Does anyone know what this shorter one is correct for? Thank you for adding to my college major of 50s Caddy parts. [home school] 

[Roger Zimmermann]

John, if I look at your picture, I see a quadruple pulley. In 1957, the compressor was driven vith a double matched belt. According to the parts book, the quadruple pulley is correct for 1957 for cars with A/C. 1956 and '58 cars with A/C had a triple pulley. Cars without A/C has a double pulley.
I hope that  it helps...

Roger

[John Morris #23947]

Thanks Roger. I cleaned, primed, painted, and photographed this pulley and did not notice the 4th groove!!

[Roger Zimmermann]

John, I really love your sense of humor!