Water Pump Pulley Poop! 95% certain on this, but I am human! I would gladly hear comments.
Jeff
All pulleys pictured are of the deep groove design. There are/may be other applications besides what is mentioned.
Will be mentioning them from left to right.
1st & 2nd pics are of the standard rear pulley design used in the normal 2 pulley set on 409's.
Left is a 3713974 ?? This is the standard rear pulley used 61-63 - 409, some HP 348 & 10-30 truck. I have never seen this number stamped into a pulley.
Right is a 3827846, visually the same except it appears to have the 3720616 reinforcement spot welded into the back of the nose and it is thicker in that area. This pulley was listed as a Corvette & 10-30 truck application, and it has the number stamped in. There was a NOS one listed on ebay 1/2/24. The numbers were jumbled. My pulley the numbers are in order but VERY faint.
3rd pic. On left is a 3770245, 1 pc 2 groove that can be used in place of the 2 piece set mentioned above. Listed as 64 409 1st design, some SBC HP & 10-30 truck. On the right is the normal 2 piece set, 3713974 rear & 3724816 front
4th pic is 64 1st design 3770245 left, 64-65 2nd design 409 center, 61-63 3713974 / 3724816 2pc set on right.
5th & 6th pics are of the pulley I have marked as coming off of a 65 JE 340hp engine. This has to be the 2nd design as the offset is different by essentially the amount Cecil shows in the chart above. This pulley did not have a number stamped in it. It's construction consists of a center cone with 2 separate V sheaves pressed & spot welded on.
The parts book lists:
64-65 pass 409 exc air cond 2nd design - 3850141
64-65 pass 409 w/air cond, exc PS, H/Per dual 4BC 2nd design - 3850977
64-65 pass 409 air cond w/ps exc h/per dual 4BC 2nd design - 3850978
Not sure which of the above 3 is the pulley I have.
From what I know a W with AC uses the 2nd groove from the back and PS then moves to a 3rd groove forward on the crank.
