Belt length issue

[FFRSpec72]

OK, so I installed power steering, the pump has the stock pulley, I have the FMS underdrive pully set (2.5" alternator pulley), I tried the K060695 (13/16" x 70"
) belt too small and then tried the K060705 (13/16" x 71 1/8") and too large, looks like there are only 2 belt in between, a K060696 (13/16" x 70 1/4) and K060703 ( 13/16" x 70 7/8), so either way it's only a little over 1/4 inch difference and not sure this is enough, any thoughts/options?

[johngeorge]

Are you using the stock tensioner? pic?

[FFRSpec72]

Are you using the stock tensioner? pic?

Yes stock tensioner, I'm out of town so I can't get a picture.

[skullandbones]

Hi FFRSpec72,

I tried doing it a little different after a couple of trips to the auto parts. I cut an old serpintine belt and measured on my pulleys taping one end with duct tape. So when I when back I had a perfect length to compare with new belts. I have a fabbed alt bracket from an original much lower than the original and a Forte PS pump bracket so it is different than any one I have seen. I think I also lengthened my tensioner tube by an inch. The point is, you can get the exact length because the belt is exact thickness and avoids any guess work. Mine was around 67.5 inches. Hope that helps. WEK.

[johngeorge]

Tony, my serpentine belt is – 5060695
and I run the tiny crank pully, stock size for alternator, and power steering, and a billet waterpump pully (not sure if this is stock size)

[FFRSpec72]

John, thanks for the pics, it looks like we run the same size pulleys from the pics, one thing I noticed is that my belt routing is the stock belt routing and you seem to be using a modified version as pointed out here, so maybe I need to try an alternate routing?

Belt-Routing-Mustang.jpg

[FFRSpec72]

So went with the small 3" crank pulley and all is well in the world, thanks John for that tip. I went with the K060695 belt now.