Blower belt not fitting need help!!!

[MY 85 GT]

Ok im going crazy here I have an 87 GT with a Powerdyne Bd11a with a 9 psi pulley...and i think a 7 inch crank or whatever stock is...The belt i have is a 6060530 too BIG so i tried a 6060510 too small i tried a 6060525 too big Im ordering a 6060515 and a 6060520 hope one of those fit any ideas on whats wrong??? Im sure i have the tensioner on right...i have no idea why i cant get a belt to fit...I need help....any suggestions would be great thanks....

 

[RacEoHolic330]

By process of elimination, one of the last 2 your ordered should fit. Run a string around the pullies and pull it taught, then measure the length of the string. That should give you a very accurate idea of the belt length. Should be either 51.5" or 52"