Anyone by chance know what the size of the drive belt is for a McCulloch Vs-57 mounted on a flathead Ford V-8?
Are you wanting the width? Length would be determined by a measuring tape IF both pulleys are operating properly and are at rest when measuring!
You need to measure width. Old Ford engines + Old 30´s Mcculloch I use Cl***ic V-Belts. Not 100% same angle, but works fine. Z, A, B... (for example B-53) are cl***ic V-Belt serie. same with teeth BX-.... Widths B = 17mm (approx 11/16") A = 13mm (approx 1/2") Z = 10mm (approx 3/8") Cl***ic belts are marked inner lenght. For example 53 = 53" = 1346mm + 69mm = outer lenght 1415mm and other way if You measure outerlenght , decrease 69mm and You know what belt You need to buy. B = +69mm to outer lenght A = +50mm to outer lenght Z = +38mm to outer lenght