Trying to figure out what size pulley came on my head unit... the pulley has no stamped size/part# on it. Is the diameter measured at the bottom of the rib relief? Top? Maybe Middle?

Is there a certain formula that can be used? E.G. overall outer diameter minus 3/4" = pulley diameter? Thanks in advance!

 

Thats weird there is no number stamped on it. Im sure Bob knows or give Procharger a shout.

 

Have you looked at both sides of the pulley? The number is always stamped on every one of them that Ive ever seen..

 

They weren't always stamped. The measurement is taken on top of the ribs, not down in the grooves.

 

Yeah... checked both sides of the pulley. Not sure, it might be an "off brand" non-ATI pulley. Thanks for the info on measuring to the top of the ribs... looks like I have a 3.75 pulley! Good thing I have a 3.4 and 3.1 on the way

 

I haven't ever seen an actual ProCharger pulley either that wasn't stamped. Bob

 

I have 3 pulleys that I got directly from Procharger that aren't stamped.

 

Wow, I've never run into that. It would make it much harder for their shipping department to know what size to ship out. Bob