[ZeGermanHam]

Originally Posted by "QUICK-SILVER"

Three groove pulley doesn't mean it's the right size. Need to measure it and see for sure.

Clay

I just found that out for myself a few days ago. I ordered a billet pulley set for late 1969-70 with PS & A/C. I have a complete set of OEM pulleys to compare with, and as you know, the factory stacked a smaller diameter single-groove A/C crank pulley behind the 2-groove WP/Alt crank pulley.

When I measured my new billet 3-groove crank pulley, I noticed that it was significantly smaller than my OEM 2-groove WP/Alt crank pulley. I soon figured out that rather than machine the billet pulley so it has a smaller diameter section for the A/C belt like factory, they just sized the entire thing down to match the smaller diameter of the A/C crank pulley. This means that it will spin the water pump slower than the OEM crank pulley would. I was kinda bummed about that. They should size them up to match the OEM WP/Alt crank pulley size, not size them down to match the A/C crank pulley size.