Guys,

I need some advices here. A friend of mine just got the 17% and 19% pulley which come with 25-060547 and 25-060535 napa belt. He is going to installed the pulley in 6 hours time. The prob here is, which belt is for which pulley?

From my understanding, use the 535 for the 19% and 547 for 17%. I think he is fitting the 17% pulley first. Shoud he uses the 535 or the 547 for the 17% pulley? Please advice..

I need fast info before the installation.. Thanks guys!

 

If one belt is obviously shorter then the other, the shorter belt
goes with the 19% pulley.

 

The 547 is the longer of the two (55 1/4 inches).

The 535 is 54 1/8 inches long.

So the 19% pully should use the 535 and the 17% should use the 547.

http://www.napabeltshose.com/downloa...IDE_FORWEB.pdf

/gary

 

Yes, but are those the right belt for the pulleys? I'm just afraid if the shortest belt is too short or long for the 19% pulley and the other belt is too long for the 17% pulley. 535 for 17 or 19 pulley?

 

gmc,

You posted first before me. Thanks for your input. I can see the difference between those two belts in terms of length but I'm just afraid it those are not the right belt for both pulley. Read somewhere that 539 is the best for 19% pulley.not sure about 17%. Can we use 535 belt with 17% pulley, too tight? too loose?

 

http://www.eurostyleseast.com/item.a...-ENGINE&Cc=MCS

 

I just checked the belt I'm using on my 17% pulley. It's a 535. I was told by Alta that it would work fine with a 19% as well. I think the 547 is actually a replacement for a stock MCS.

 

now im confused, some said that the stock belt can be used with 15% and 17%, just like the link Ted posted.

GMC, any problem so far? Belt snapped or slipped?

 

I believe that the link that I posted said that the
stock belt or 539 can be used for the 15% pulley.
I believe that the stock belt is shorter then the 539.

17% - 539
19% - 535

 

The stock belt probably can be used with a 17% in most cases. There's some amount of adjustability in the tensioner for obvious reasons.

My belt is in great shape - about 8000 miles on it and the 17% pulley, no slipping or cracking or any visible wear. I don't track / race / autox but I do enjoy driving spiritedly on the street.

The thing with the belt length is that you don't want the tensioner to end up all the way tight or all the way loose if you can avoid it. There are probably people that have heated opinions on where the tensioner should be when a new belt is properly installed - as for me I just wanted it to have at least half it's overall range of travel remaining when the belt was new and with the 535 I think I got about 2/3rds of the travel remaining, which I was happy with.

/gary

 

The stock belt is definitely longer than the one that should be used with a 19% pulley.

Also, there are people who have used the (shorter than stock) 535 belt with a 15% pulley (Andy of Ross-Tech is one according to an old post of his I read) with good results.

There are probably a few engines that require a longer or shorter belt than the vast majority just due to variations in locations of the alternator / AC compressor / supercharger.

 

GMC,

Are you saying that he should do some adjustments at the tensioner with the 17% pulley, not just plug and play? IF yes, how much?

Im using 15% and it was just plug and play, I mean I didnt adjust anything.

 

Detonics, this info was searched and found in 20 sec. in Beneath The Bonnet

https://www.northamericanmotoring.co...gatorback+belt

 

Thanks guys, really appreciate your help. Fitted the 17% pulley with 535 belt....