1970 LS5 Belts

[Allen N.]

I am restoring a 1970 LS5 with N40 and no A/C. My research indicates the correct belts are:

water pump and crank = GM 3952336

water pump, crank and p/s pump = GM 3940992

p/s pump and alternator = GM 3878243

Paragon and Quanta have these belts. Which company's belts look the most original and score the best when judged?

Paragon offers two of the belts in cut or wrapped. Which is more original?

Quanta offers the 3878243 belt for 1969 LS5, but for a 1970 LS5 they list a 3845642. Is the 3878243 the correct belt for my application?

Thanks,
Allen

[Mark E.]

Re: 1970 LS5 Belts

Hi Allen,

Does the AIM provide belt PNs? Be sure to reference the applicable RPO sheets. If Quanta lists LS5 for 1969, how much should we trust their PNs?

The Chevy Parts Catalogs may list service PNs for a particular time period, so there's probably several choices specified depending on the book's vintage. The AIM PN, which is likely the production PN, will probably judge best.

I believe wrapped belts are used for 1970.

Sometimes original belt sizes are too short/long for a particular car, forcing use of a different size belt(s), or creative belt adjustment.

[Patrick H.]

Re: 1970 LS5 Belts

Paragon sells Quanta belts, and has them direct-shipped to you. The net price will be the same, so I'd just call Quanta and discuss it with them.

[Terry M.]

Re: 1970 LS5 Belts

My 1970, not a BB, came with some wrapped belts and some cut. I would not be concerned about this feature.

I can't tell you what all judges look for, but the main features are the style of logo and size (embossed or ink stamped) and accurate size so that the adjusting item is in the center of the adjustment range.

[Patrick H.]

Re: 1970 LS5 Belts

the main features are the style of logo and size (embossed or ink stamped) and accurate size so that the adjusting item is in the center of the adjustment range.

And, that they're not cogged. If they're the modern cogged style then don't even bother worrying about size or anything else.

[Allen N.]

Re: 1970 LS5 Belts

I called Dave at Quanta. He said they have been selling the 3845642 belt for this application for 20 years. The early AIM Quanta is using that has UPC N40 Sheet A6 which was redrawn and redesigned 12-23-69 shows belt routing on the lower left hand corner of the sheet with the 3845642 belt as item number 11. It also has the 3878243 belt on UPC N40 Sheet A8.

My AIM has UPC N40 Sheet A6 which was redrawn and redesigned 5-28-70 has no belts on this sheet. My AIM has the 3878243 belt on UPC N40 Sheet A8.

So based on my AIM, I am inclined to use the 3878243 belt.

[Terry M.]

Re: 1970 LS5 Belts

And, that they're not cogged. If they're the modern cogged style then don't even bother worrying about size or anything else.

Good point, which I forgot. I was looking at the trees and missed the forest.

[Allen N.]

Re: 1970 LS5 Belts

How about the question of whether the 3878243 belt or the 3845642 belt is correct. Does anyone know which one is correct?

Thanks,
Allen