[javadog]

Tom,

You don't mention what year car for which you need a belt, so I am going to make an educated guess.

In 1980 Porsche changed the fan size used on the 911SC to the larger one used on the turbo. They produced part number 999.192.176.50, which was for a 9.5x710mm belt made by Goodyear. They also changed the method of adjustment, which is seldom discussed. I'll quote from the introductory Service Information book for the 1980 models:

"Only the approved belt from Goodyear, Part No. 999.192.176.50, may be used.
The new belt must be tightened more than previously.
Adjustment: Tighten belt as usual (10 to 15mm deflection). Then reduce the number of spacers between the pulley halves by one. (ca. 5mm belt deflection)."

I have found that Pelican can get (order) any part from Porsche, if they don't stock it. In this case, they may be using a belt, supplied by the aftermarket, that may be a slighty different size or have a different taper. Perhaps, if you call them and let them know the problem that you're having, they'll add another line item to the catalog (or change the part they supply) and people will quit having this problem.

Hope this helps,
JR