Can you use a smaller pully with the whipple supercharger to gain more boost and if so where can you get one and what size can you use? Also can you use an underdrive pully if you have a supercharger?

Yes you can, I use a 2.5 inch pulley on mine. You must use a 1" shorter belt when you do the swap from the stock 2.75" though. I wouldn't go any smaller then 2.5 though because you start to outflow the what the mass air is capable of reading, see post " 3.0+18lbs of boost=pop!".

If you use an underdrive pulley with the Whipple you will be lowering the boost amount.

I got my pulleys straight from Whipple but never really paid anything for them, from the ones I've seen on ebay though they go for around $100 each :eek: .

Later Doug904.

If i put a smaller pully on, would I have to have my computer reflashed or have to have the truck dyno'd to check to see if the air fuel mix is correct or will the truck adjust itself?

With a simple 2.5 inch you'll be fine, anything smaller and you need a dyno tune along with a larger Mass air, like off a 4.6 or 5.4, but remember you can't just sling this mass air on, you'll have to have it compensated for on the tune.

Later Doug904.

What size is the Whipple MAF. Mine is a 65mm, it is suppose to flow well over 320HP, or is it a transfer function issue?

do you know what length belt you would need with the 2.5" pully?

Remember, more boost=higher chance of distructive detonation.
3.0L's do not like high boost unless you have something to correct the detonation issues. Doug904 can vouch for me when I say taking of timing is effective, but NOT a good idea from a performance aspect. Water injection, lowered compression and other ideas need to be carefully considered BEFORE you put that pulley on. I recommend having a few miles under your current set up, and verify it with a wide O2 dyno run, before you look to a smaller pulley. Boost is addictive...

your right I probably will wait to try the smaller pully especially since it will viod the one year warrenty on the supercharger.