'67 427/390 A/C pulley configuration & dimensions

[James West (18379)]

I need to know what the correct pulley configuration and groove width is for a 427/390 a/c equipped '67 Corvette. Are both the water pump and crankshaft pulley a 2 groove or 3 groove pulley? The car does not have power steering or a.i.r. What is the groove width for the correct pulley? When using or trying to turn on the a/c, the repro belt does not have enough grip to turn the a/c compressor without smoking the belt. All the vendors give the same p/n for the a/c belt. I am beginning to think I may not have the correct pulleys. Anyone have any pictures of the correct pulley arrangement they would be willing to send me?

Also could someone recommend a replacement belt part number from one a parts store or the current GM replacement p/n?

Thanks,

James West

[Stephen Lavigne (7553)]

Re: '67 427/390 A/C pulley configuration & dimensi

I don't have AC on my 67, however the belt configuration is in the AIM. Check it out. It'll show which pulleys have how many grooves......

[Joe Lucia (12484)]

Re: '67 427/390 A/C pulley configuration & dimensi

James-----

I can't provide pulley width information at the moment as I don't feel like going out, digging out the pullies and measuring them. However, I can tell you the pullies you need.

The cranksfat pulley is a cast iron pulley with 2 grooves. It is GM #3863108 and it's 6-3/4" OD.

The waterpump pulley should be a 3 groove pulley of GM #3889372. That pulley was discontinued in June, 1971 and replaced by GM #3995644. So, either of these pullies should work. They are of 5-1/2" OD.

I have very conflicting information regarding the A/C drive belt. The original PRODUCTION belt was SUPPOSEDLY of GM #3889376. That belt is a 15/32" X 45-3/4" belt. It was discontinued in 1970. It would seem to me that a 45-3/4" belt would be way too long, but maybe not.

The current GM SERVICE belt for the application is GM #9433735. That belt is 7/16" X 41-1/2" long. That still seems too long to me, but maybe not. It's still available from GM for about 16 bucks, GM list.

The pulley configuration is pretty simple. The inner groove on the waterpump pulley and crank pulley are driven by a captured belt. The next outermost groove connects the crank, waterpump and alternator. The outermost waterpump pulley groove drives the A/C compressor.