Belt sizes

[1987 GMC Jimmy]

Pull it and plug off the exhaust manifolds.

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Oh, that’s been done a while ago. I mean for the poor S.O.B.s that have to undergo an emissions inspection.

 

[Turbo4whl]

Aftermarket V-belts all have a common numbering system. The Napa number in the picture, 25-7435 is as follows:

The 25- is Napa's code for the Premium XL belt.

The 7 is the width of the belt **

The 435 is the length.. 43.5 inches

** A Dayco or a Gates number on the belt may use a different code for the width, but the last 3 digits are always the length.

And of course, any pre numbers on the belt refer to that manufacture's design. Like a Gates Green Strip belt etc.

 

[Ricko1966]

Call me crazy, but I like the v-belts without the smog pump.

Okay you are crazy.Not sure how that helped but, I've honored your request.

 

[MisterB]

Changed the belts today. Turns out both belts ARE the same size. I was able to see the part number on both old ones and they match the new ones in size and part number. Got everything buttoned up and everything works great.

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[Vbb199]

Go to the wrecking yard and pull the entire serpintine system off a Vortec sb. It's the best "less than a $100" upgrade you can do. Dump the ancient Vbelts.

Lol I was thinking the same thing.

 

[MisterB]

Lol I was thinking the same thing.

Seems like too much fuss for something that works just fine

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[Vbb199]

Seems like too much fuss for something that works just fine

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It really is, for something that works fine as it is (your truck)
At least on the tbi small and big blocks, the power steering pump is a TOTAL PAIN to get on and off.

 

[SquareRoot]

Seems like too much fuss for something that works just fine

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Nah! This more gooder!

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[highdesertrange]

first thanks for the follow up Mister.

the thing with serpentine belts is if you lose anything you are DOA. with v-belts you have some redundancy. I still use my truck and I often find myself a fricking long, long way from any type of parts store. so I need it to be as dependable as possible. and if something should fail, a backup plan B is always welcome. beside the wow and the that's cool factor I don't get it. highdesertranger

 

[MisterB]

first thanks for the follow up Mister.

the thing with serpentine belts is if you lose anything you are DOA. with v-belts you have some redundancy. I still use my truck and I often find myself a fricking long, long way from any type of parts store. so I need it to be as dependable as possible. and if something should fail, a backup plan B is always welcome. beside the wow and the that's cool factor I don't get it. highdesertranger

Since my old belts were still in pretty decent shape, I saved them and put them in the packages from the new belts, wrote "used" on the packages, and put them in my toolbox in the truck. That way if something breaks or slips off I can repair it to get myself home

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[C10MixMaster]

When i did my engine swap it came with a complete serpentine setup. So switching would have been kinda easy. I ended up staying with my v belt setup. First of power steering and a/c lines will need to be changed or fabricated alternator is usually on the opposite side also. Second do the benefits outweigh the trouble. You always see that serpentine setup free up tons of horsepower yet i have not found where anyone has shown this with a dyno. I did find a paper on testing done on industrial belts and pulleys i think it was published by dayton? . I broke down different belt a pulley sizes and measured the frictional loss of each. Basically on average each pulley will cost you about 1/3 of a horsepower and that was for a v or flat belt. Take your typical serpentine setup, it will have 6 or 7 pulleys/tensioners meaning it's going to cost you about 2 to 2.33 hp from belt friction. Now a old v belt setup like on my truck with ac it has 9 pulleys meaning im losing about 3 hp to belt friction. Is it worth the trouble to gain one hp or less? Plus i like 2 belts on the water pump.

 

[SquareRoot]

Serp belts are cheap. $15 for my gates. Changing the belt takes a 5/8 socket on the end of a breaker bar or 1/2 drive ratchet. The act itself takes 30 seconds. Not so with v belts.

 

[80BrownK10]

Serp belts are cheap. $15 for my gates. Changing the belt takes a 5/8 socket on the end of a breaker bar or 1/2 drive ratchet. The act itself takes 30 seconds. Not so with v belts.

I might change them every decade, so I'm with the other guys, it looks neat but not something I want to spend a day doing.

 

[Vbb199]

Meh.
If the truck came with v belts, I'm not gonna take the time to convert.
Works fine.

If the truck came with serpentine, I'm certainly not going to switch to v belt.

If the truck has nothing and I have a choice like with my 502, I went gen 5 BBC serp setup.

Either or, 30 sec, the serp belt can be replaced, no big ****.

Whether it's a v belt drive or serp, keep spares in the truck like @MisterB lol

 

[bucket]

Meh.
If the truck came with v belts, I'm not gonna take the time to convert.
Works fine.

If the truck came with serpentine, I'm certainly not going to switch to v belt.

If the truck has nothing and I have a choice like with my 502, I went gen 5 BBC serp setup.

Either or, 30 sec, the serp belt can be replaced, no big ****.

Whether it's a v belt drive or serp, keep spares in the truck like @MisterB lol

I'm in the same camp. If it came with v-belts, that's fine. If it came with a serpentine setup, that's fine too. If starting from scratch, I'll install a later model serpentine setup.