L-71 Alternator Belt

[Richard G.]

Gentlemen

What is the correct alternator fanbelt number for a late production 1969 L-71 w/o power steering, 3940991?

Thanks

Rich

[Joe L.]

Re: L-71 Alternator Belt

Rich-----

Yes, GM #3940991 was the PRODUCTION alternator belt. This belt was a 15/32" X 53-1/2" belt. This is a real "oddball" size that you'll only obtain these days in a reproduction belt. For quite a few years, the belt that GM sold in SERVICE for this application was the GM #3871257. That belt was 3/8" X 54-3/4". It's not inconceivable that some of these MAY have found their way into PRODUCTION, too.

[Jack H.]

Re: L-71 Alternator Belt

'Correct' PN will depend on your objective: (1)as delivered from the factory with cloth wrapped belt, or (2) GM service replacement die cut belt. The difference is the original production belts that were cloth wrapped were more narrow and rode LOW in the pulley groves. The 'improved' service replacement belts were wider and rode HIGHER on the pulleys and thus were longer in length to compensate for the higher ride. There's no question, the die cut version of the belt had a MUCH better service life profile!!!!

You should find the factory original, narrow, cloth wrapped belt's PN called out in your copy of the AIM. My copy of the 53-72 Corvette Parts & Accessory Manual calls for 391213 as the alternator belt to use on '69 BB with Sp High Perf and w/o PS defining this as a 3/8 x 54.4 inch belt.

[Richard G.]

Re: L-71 Alternator Belt

Joe

As usual, thanks for your help. One other question comes to mind, is there a "wrap" reproduction idler belt, I've only seen "Cut" Belts? Some of the original parts on my car are getting older and I'm trying to obtain replacements for the collection.

Thanks Again

Rich

[Joe L.]

Re: L-71 Alternator Belt

Rich-----

As far as I know, there are reproductions of all of the original wrap-construction belts available. Wrap construction was used on most belts through the 1972 model year.