Help w/ the rite belt..

[jims427400]

So far I've tried 3 water pump drive belts for the 68 (400hp-no power steering,brakes or air) and they've all been too long or too short. I talked to the Paragon CS and they helped me determine that at some point Bubba changed my water pump pulley. I guess all 68 427s came w/a 3 groove pulley. I now have a 2 groove. A new pulley is $200 bucks. Is there a way to measure my circumferance and or a spicific dia. belt from a vender. Any recommendations and venders anybody.. I'd rather spend my $200 bucks on something more productive.
Currently just running the alt. belt but looks a little shaky..:bash

 

[bmotojoe]

To measure the belt is simple, with the adjustment for the tension back all the way or most of the way back (loose) just cut a length of heavy string and feed it around all pulleys involved. Just mark with a felt marker where the end of the string and remaining string meets when pulled semi-tight, this is the total length of the belt needed. Now you will have to determine what pitch of belt you will need. The pitch of the belt is critical to insure the belt fits the pulley correctly. If you measure the alternator pulley from outside to outside where the belt fits and it matches the water pump pulley measurement then you have the pitch of the belt. Any good auto parts house can take the length you give them from the string measurement and cross it to a belt number. Should not be any problem unless you deal with inexperienced parts people.
Brian

 

[JohnZ]

Since today's belts are narrower than the original 60's GM belts, crossing the numbers doesn't always work. On project cars, I mark a length of clothesline rope for the length I want, take it to the parts store, and get three belts. One the same length I marked, one 1/2" shorter, and one 1/2" longer, and return the two that didn't work.