fan belt size

[53 moneypit]

I am a bit confused and maybe someone can help. The fan belt on my 53 Chevy PU measures 5/8" at the widest (the outside dimension), however the Chevrolet Truck spec sheets I got from GM says it should be 3/8".

I want to replace the small pulley on the alternator I installed with a wider one so that I can use the old pulley that matches the water pump and crankshaft pulleys. Is it 5/8 or 3/8?

Thanks in advance.

 

[bennyhunch]

Hi Chuck
I would measure the pulleys that you want to use and find one for the alternator that matches. Someone may have changed pulleys along the way.
Steve