70 alternator belt

[Roberto L.]

Hello friends, I have a base 70 coupe, no PS, no AC, manual. It uses a captured belt (water pump) and an adjustable alt. belt. I want to change this one after a long use. Although I have the present alt belt as a reference, I would like to know the correct size, assuming the pulleys are stock.

In my country (Argentina) I can get Goodyear belts and other less known brands.

Thanks in advance, Roberto, NCRS #30019, RMC

[Jack H.]

Re: 70 alternator belt

Originals were cloth wrapped and more narrow than current service replacements allowing them to sit lower in the pulleys and be shorter in overall length. The 1972 Corvette P&A Catalog calls out the following for service replacement belts for your car.

Gen/Alt 3861946 3/8 by 54 inches
Water Pump 3941116 3/8 by 35 1/8 inches

For a metric sized belt (0.440 wide), my crib notes say to increase the length of the belts to 55 and 36.5 inches respectively...

[Roberto L.]

Thanks! *NM*