Having trouble finding the right fan belt size. I have a 454 in my 68 with a long water pump. I've changed the stock alternator brackets to March billet aluminum that has an adjustable rod for the top. This has brought my alternator in a good bit from the stock location which means my stock fan belt (46") is too long. I've tried a 44" & a 45" both being too short. Has anyone else done this switch and if so what size belt did you use? Or is it just trail and error? Thanks graemlins/waving.gif

Try a 45-1/2" belt. If you are using Gates belts it's easy. If the number is 7440, get a 7445. When the number goes up by 5, the length changes by 1/2". A 7450 would be 1" longer than a 7440.

Thanks Carl,I'll stop and get one on my way home from work.

I use this setup:
http://www.blackmountainprecision.com/Chevrolet-big-block.htm

CarlC..45-1/2" worked great. Thanks

Dawg...that is an awesome set-up, now I wish I had seen it first. Maybe next winter I'll make the switch. Thanks!!