Alt belt length

Can someone tell me what the correct alternator belt length for a '68 302 w/o AC is? Different vendors have different lengths.

Many Thanks…

The M-E-L MPC (April 1973) lists 2;
US utilized a C9PZ-8620-S (JB-412) 15/32" x 41 1/4"
Canada only CC4TZ-8A615-R 15/32" x 40 1/4"

CJPonyParts shows a 40.5" length with .44 width.
Mustangs unlimited has a 41.25" with a .47 width listed.
Summit has a 45" with a .437 as the correct V-belt. (That seems a bit too long)
West coast doesn’t have anything listed.
Want a Goodyear Gatorback belt from Summit and they do come in shorter lengths so I figure a 40.5 will work fine??

Too many variables to list something like that. Change one of the pulleys, and everything changes.
Some after market water pumps change the position of the center hub.