Re-posting this information (April 2023) regarding belts and issues surround the belt.  

Highway Stars has received calls from customers asking if a belt is the correct size because they are experiencing issues. 

FACT: If you have purchased the drive belt from Highway Stars for your "ALL-STOCK 86/87 Turbo Regal", then we can ensure that you, YOU HAVE PURCHASED THE CORRECT BELT"

We can not ensure this is the case if:  you purchased the belt elsewhere, OR if your vehicle has any of the variables listed below. 

The questions then comes:

a. Do you have ALL factory stock pulleys on the vehicle?  Have you verified this?

Water pump pulley?

Crank shaft pulley?

Power steering pump pulley?

AC pulley?

Alternator pulley?

Belt tensioner pulley?

b. Do you have an aftermarket belt tensioner on the vehicle?

c. Has the alternator been changed from the factory stock alternator? 

d. There are many catalog errors for aftermarket belts that may not be advertised correctly for the fitment.

If you have purchased a drive belt from an auto parts store/seller there is a good chance that you have purchased a K060640,  This belt is way too long for the stock 86/87 Turbo Regal/Grand National.

Despite having the correct belt from Highway Stars, all the factors listed in a,b,c,d will introduce variables that may be contributing to your issues. 

The photo above will depict a perfectly sized belt on an 86/87 Grand National.  This grand national is a bone stock factory original vehicle.  See how the indicator marks line up horizontally.  Belts that align within the horizontal indication on the left side which falls within the perimeter of the rectangle on the right size is an acceptable range.

Beyond this range (either above or below the rectangle) will indicate something is causing it not to be correct. (Not necessarily the belt).