Finishing the build, wanted to know if any of you guys knew the factory 1969 455 alternator belt length? Im measuring 58" but wanted to know what the book says. My chiltons manual is no help, nor can I nail it down online.

Car does had AC, but this belt does not touch that pulley.

 

Rock Auto's web site shows part #15580 from multiple belt manufacturers, so your 58" measurement looks to correlate to the listing.