PSI/481x Pulley question

I have a AJ 481x and just put a PSI screw on it. I have measured the C/L and have the right belt. I am trying to use a 92% overdrive (rules) and the only belt I can use seems to be too long. I currently have a 71 tooth lower a 38 upper with a 1792 belt that measures 224t and has a 136t pulley maximum. The next shorter belt is TOO short (200t @ 88t max). I am wondering how these guys are doing this, are they using spacers under the blower? I can increase my upper to a 40t (I think it is the largest made) and my lower to a 76t, but I am giving up 2% overdrive and I'm afraid it will still be too short.

I know I am not the first to travel down this path, any help would be appreciated...
Thanks Jim Costa

 

belt

If I added eight that is only 109 teeth with both pulleys. Don

 

pulleys

Sorry, forgot to ask, what is the C/C distance? I will look up a few things in my book. Don

 

It measured 24.5" crank to blower... I'm surprised there isn't a belt that is between the 1600 and the 1792, they are 7.5" different in length.

 

belts

Here is what you got for belts
1520-8mm-75 170 tooth 59.520 in
1600-8mm-75 200 tooth 63 in
1760-8mm-75-220 tooth 69.300
1520-8mm-75-190 tooth 60.00 in
Not sure if the are all GT or not. They are Kevlar + rubber Don

 

Can you run a taller set of pulley's and go to the longer belt ??

 

belt length

Looks like a 14mm will work and give him 91.7 over with a 46 +24. But I don't know what drive he has? The only 481X I ever say had a 2 in spacer under it. Maybe a large idler will help out also. There is a way. It just will take some thinking and maybe some more money. what do those ADRL guy run? there is some 481 stuff out there.

 

pulleys

I'm in the same boat with my Chevy. 24 inch between pulleys. What is your deck ht? I've seen a spacer under the blower on 481x before.
There is a 1710-11mm. I'm considering it but the price is outrageous.

 

I did find that RCD makes pulleys that will work. An 88 lower and a 46 upper pulley gives me 91.3% overdrive with a 134 tooth combination, belt is good up to 136 teeth. This will eliminate having to use any spacers.
Thanks for helping point me in the right direction. Jim

 

Watch what rcd tells you, i bought 3 sets of pulleys and belts nothing worked that they sent,all parts were none returnable since the pulleys were considered special order.The 11mm belt and pulleys worked the best with small idler pulley,I have an assortment of new 8mm and 14mm sitting on the shelf,nothing like spending $4000.00 dollars to increase the overdrive from 116 to 128.

 

we run a 481x with a c rotor with 11mm stuff no problem 52 bottom and 27 top puts you at 92 over Doc

 

belt length

I don't have a chart for the 11mm stuff. But if it works for other people it should work for you. It really is not that hard to figure it out. If the larger pulleys will word with your drive then go that way. Just figure it out with the tooth count for the distance like I said earlier. Good luck. Don

 

Like a couple posts up, look at the diameter of the idler. You can adjust quite a bit by just changing that.

 

11mm you can run up to 116 over with standard intake 54 botton 25 top, cut it down 250 and you can go 124 56/25