I'm putting together a 302 eng for a Z with all original pulleys and smog pump. I believe the Alternator belt w/smog pump is a GM #3932457 but I'm getting conflicting info as to the size or length of belt. I've seen an actual #2457 belt with 46.5 embossed into the belt as the length and then I've seen some places list the belt as 39.5" ..... So does anyone know which is the correct length. I would expect the longest would be correct since using a smog pump but confused since I've seen both with the same p/n yet different length size.
Thanx for any help
DC