67 427/400 A/C Belts

[Stephen G.]

Quanta says that all the belts for these cars are 3/8" with the exception of the A/C. All of the belts on my car are 15/32. None are original. With the deep groove pulleys installed (all I believe to be correct & original) 3/8 belts will not work.

I searched the discussions but can't seem to find anything definitive.

[Joe L.]

Re: 67 427/400 A/C Belts

Quanta says that all the belts for these cars are 3/8" with the exception of the A/C. All of the belts on my car are 15/32. None are original. With the deep groove pulleys installed (all I believe to be correct & original) 3/8 belts will not work.

I searched the discussions but can't seem to find anything definitive.

Stephen-----


GM says the same thing as Quanta. All the belts except the A/C belt were supposed to be 3/8" belts. The A/C compressor belt was 15/32". As a matter of fact, most Corvette belt applications in the C2-early C3 period were 3/8". After about 1973 these changed to 7/16" belts and 7/16" belts were then also specified for SERVICE for most earlier applications, too.

[Stephen G.]

Re: 67 427/400 A/C Belts

Thanks Joe. I guess I'm just going to have to do my own thing because the car just won't run with 3/8" belts.

[Joe L.]

Re: 67 427/400 A/C Belts

Thanks Joe. I guess I'm just going to have to do my own thing because the car just won't run with 3/8" belts.

Stephen-----


You might have a hard time finding narrower belts. These days, I think 3/8" is about the narrowest belt generally available.

I do not understand why the 3/8 belts won't work for you. I just installed a set of 3/8 belts on a big block that has pretty much the same pullies you have. In fact, I've also installed 7/16" belts on both big block and small block pullies with no problem, at all. So, I just cannot understand why you are having problems.

[Stephen G.]

Re: 67 427/400 A/C Belts

I think you misunderstood me. The 3/8" belts bottom out on the pulley and don't run on the sides. They are too narrow. With 3/8" belts and a 15/32 AC belt the AC compressor stalls and actually slips the water pump belt.

When I got the car it had all 15/32 belts. The alternator & AC were Gates and the water pump was a service replacement GM. They ran fine. When I put in a new radiator I thought I would get the Quanta's and try and get the car more correct.

[Joe L.]

Re: 67 427/400 A/C Belts

I think you misunderstood me. The 3/8" belts bottom out on the pulley and don't run on the sides. They are too narrow. With 3/8" belts and a 15/32 AC belt the AC compressor stalls and actually slips the water pump belt.

When I got the car it had all 15/32 belts. The alternator & AC were Gates and the water pump was a service replacement GM. They ran fine. When I put in a new radiator I thought I would get the Quanta's and try and get the car more correct.

Stephen------


I have NOS examples of just about every Corvette big block pulley ever made as well as original NOS GM belts from the 60's, 7/16" GM belts from the 70's and 80's, and modern-day 3/8" belts. When I get a chance, I'm going to have to go out and try these belts in the various pullies and see "what gives" here.

[Stephen G.]

Re: 67 427/400 A/C Belts

That would be great. I'll get you my pulley part number when I get back to the garage in the AM..

[Stephen G.]

Re: 67 427/400 A/C Belts

Joe

My pulley is a 3889372