The LCF doors might not allow the window to roll all the way down as Mike B said. The Chevy glass is all the same as the pick-up trucks - I would assume it's the same for your GMC.


1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy