Alright i have a underdrive pulley crank. I have messured it with the string and that got me no where, i have called speed inc got me no where. Have tried to use the stock belt and that me no where. Im losing my mind have had this car down for 3 years and thats when i bought the underdrive and dont remember any information about brand or % nothing.

can anyone help me out. just really frustrated at this point.

 

Measure the belt length you need buy a couple that are all different lengths but close to what you measured use the one that fits best and return the others. or iff you dying to get it on the road with out doing to much work to figure things out Use the stock pulley and belt.

 

i already tried buying a bunch of belts that didnt help much. seems that my parts guys arent helping out.

 

what are the different % options ?