My 450 gmc coe with the 302 squeals the belt at high rpm. I've tightend "the wizz" out of the belt, but upon looking at it closer I think that the belt is not the right width. It runs down in the bottom of the pulley grooves. All that is on the belt is a NAPA number(25-11000), but I think that it is a "A" belt or about 1/2" width. I would guess it needs a "B" width belt, but don't know. Does anyone know which width belt is correct and perhaps what length. I've got to pull the alternator again so now is a good time to make the switch. BTW all the belt pulls is the alternator and the fan. Thanks all.
Scott

1947, 1950, & 1952 Chevrolet 1/2 ton
1952 GMC 450 series Cab Over Engine
1946 Chevrolet 2 Ton