67 327/300 pulley - trash or treasure

[Jeff Bukowski]

I'm changing over to what I think is the correct pulley setup for a 327/300 with power steering ( no air). Attached is a picture of the cast iron pulley I removed from the car.
Can anyone tell me what setup (if any) this pulley would be correct for.

Here's a couple of clues.

1) it bolted up nicely to the harmonic balancer with 3 correct looking bolts
2) there is a raised lip on the back that fits perfectly into the hole in the center of the balancer
3) ACME 04296 and 4060-6SP-64051
4) the center hole has an ID of about 7/8 of an inch. The harmonic balancer bolt I removed was about 4 1/2 inches long. I don't think my crank should be drilled for a bolt but its there
5) It is a 2 grove pulley

[Mike McKown]

Re: 67 327/300 pulley - trash or treasure

Some trucks used a cast iron pulley like your picture. Which ones, I can't tell you.

[Joe L.]

Re: 67 327/300 pulley - trash or treasure

Mike and Jeff-----

Mike's got it---this is a truck pulley which was generally used on some MD and HD trucks. This, particular, pulley may be an aftermarket replacement for same or it may be an "outsourced" pulley originally used by GM. My guess would be that it's the former, though. I would say, then, that this is an aftermarket replacement for the GM #3911549 pulley.

With one possible exception, no 1955-82 Corvette small block ever used a cast iron harmonic balancer pulley. The possible exception was 1970-72 ZR-1. A cast iron harmonic balancer pulley borrowed from the MD/HD truck "parts bin" was scheduled to be used on those applications. The few known-original cars that I have knowledge of don't have this pulley, though. So, whether it was ever originally installed on any I do not know. But, I know that it was scheduled to be used for the application. Since so few of these cars were built and since the standard LT-1 harmonic balancer pulley, GM #3858533, will functionally interchange with this pulley perfectly, it may be that the folks at St. Louis just installed that pulley whether the engine was in a ZR-1 optioned car, or not. Of course, in doing so they deprived the ZR-1 buyer of one element of "uniqueness" but I'll bet none of those buyers even knew that their car had the wrong pulley installed.