i just bought a march pulley for my gt. and i was look @ the size differencr between the two and the march one seems smaller. is that normal and am i going to need to by a different belt?

 

It and "underdrive" pulley, so yes it's smaller--if you just got the crank pulley then you will need a shorter belt.

 

you can get a overdrive waterpump pulley for it to fit i have a march pulley myself, i didnt really notice a difference with them on though.

 

arent march pullys piggy back? a no go if i recall correctly

 

It depends on which set/pulley you buy--they make both.

They are however all made of aluminum which is easier and cheaper to machine because it is much softer than iron (Steeda's SFI crank pulley is iron). Aluminum is also a crappy material from which to make poly-V, or any belt drive, pulley--because it is much softer than iron.

Front main seal problems with aluminum crank pulleys are not uncommon--because aluminum is much softer than iron--and abrasive particles that get embedded in the seal will chew into the aluminum much faster than they would chew up iron.

March says they hard coat the sealing surface of the pulley hub which will make things better, but still not as good as iron.

The drive belt itself will also get abrasive particles embedded in it, which can chew up the drive surfaces of the "much softer than iron" aluminum pulleys.

Did I mention that aluminum is much softer than iron?

This may not be an issue for a showcar, race only, or weekend cruiser, however if yours is a DD like mine (25k+ miles a year) then it can be a yet another thing to go wrong down the road (no pun intended)...