i figure that my 4lb should be the right size for a 6lb lower and 2lb upper, because since a 2lb upper is smaller in diameter then it sould come out to about the same right??

 

It will probably fit. The crank pulley has a lot more circumference than just the upper.

 

your doing a 6# lower and a 2# upper? That's a lotta boost. I've got a 4# lower and a 2.80 upper. I was able to use the same belt, you should to. Good luck with the new set up if you get it.
Shane

 

I have a 6 lower and a 2 upper(interchangeable). I am able to use the same Gatorback belt with either the 6/stock or the 6/2 combo.

I will tell you though that my gain with the 2 upper was not much compared to the heat I was getting due to overspinning the factory supercharger. I am now back to the 6 lower and stock sized upper.


I would love to find out what results you get at the track.

Rocks