Ive got a set of Mazdaracing competition pulleys, but I need the serpentine belt properly sized for the pullies. Ive tried ordering one from mazdaracing themselves, but they never answer their phone, and never return my emails. Anyone know the size, part number, etc of the proper belt?

 

I hope you aren't running that setup on a street car! They are ONLY to be used for high rpm track cars. I have those pullies. The main pulley is WAY too small. It is smaller than the water pump pulley. You do not want to drive around with them on the street, especially on a T-II. I don't remember the belt length. Just take a length of string and pull it around the pullies to see the total distance. Do this with the alternator all the way up and all the way down to give you a range. Then try to aim for the middle of it in length when you go to the autoparts store to buy it. This will get you close at the very least. From there it might be a little trial and error.

 

Yea, I was planning on putting it on my street car, would it really underdrive the waterpump enough to cause overheating?

 

Yes, the water pump pulley is sized to reduce the rpm's because running at 7000+ the factory pumps begin to cavitate and reduce flow. So on the other side of the coin if the car is seeing street use it may very well under-work the water pump and your temps will rocket.