I need to replace the serpentine belt on my 1990 formula 350. Problem is I have been looking for a while now and everything I read says a different length. What is the exact length? It's a bone stock motor so whatever stock is that's what I need. Thanks in advance.

 

You need a Gates P/N K060945 or equivalent. Nominal length 95-1/8".

Keep in mind that belt manufacturers will try to make one part number fit as many applications as possible. This is why you see different lengths. The belt tensioner should be able to accommodate these differences.

 

How about a factory part number

 

The top layer of the belt has torn off, lol, otherwise that would be the way to go. Thanks for the help though guys.

 

This shouldn't be this hard. Since your engine is stock why are you trying to find a belt of a certain length? Just buy one for your application and it will fit.

http://www.rockauto.com/catalog/x,ca...,parttype,8900

Looking at he link, it appears that lengths of the four "Standard Replacement" belts (you don't want the "Economy" ones) differ by 3/4". Regardless of whether it's "effective" length and "overall" length, the belt tensioner should accommodate this small difference in length.

The Gates part (K060945) description actually lists, "Formula".

 

The length is slightly different based on which routing you use. Based on the pictures, I believe the 89 routing uses a longer belt.
Example; If the belt is too long for the 88 routing, try the 89. Likewise, if too short for 89, the 88 route might work.

 

Bring the old one in to match it up.