I recently bought a zc block to replace my a6 block since it has a 2in hole near the exhaust manifold from a rod! I got the ZC full short block home and noticed it had a lightweight Underdrive pulley on the crank. I would like to keep the u/d pulley but I am not sure what belts i should use will stock work? If not does anyone know any that will? Does the pulley do much as far as performance?

thanks

looks like this

 

try the stock belts, if they dont work, wrap a string around the pully's to measure the length of the belt you will need. Take the old belt and the measurement to a parts store, they can help you out.

 

are you going to try and mate an A6 head onto a ZC block? Because if you are you're going to be unhappy.

 

Im going with a z6 head with apexi vafc. Maybe DOHC ZC pistons (pm7?) and PG7 ECU. Not sure how the ECU would work with z6 head and apex'i vafc.

 

it will all work out nicely if it is a SOHC ZC. But i think your compression might be a little bit too high with the ZC pistons & Z6 head. Not exatly sure though, i was calculating mine for a Y8 head and ended up at well over 12:1 static.