First let me say WELCOME 04 Silver [smilie=wavey.gif]
And thanks for joining
I've been running the SFPH upper pulley (Dial-Ur-Boost) set up for @ 3 years now.
DEF the best on the market, and you can change uppers in less than 2 minutes if
your in a hurry. (3 if your not, hehehehe) 1 minute if you really rush
I currently have the 2.93 (thats stock size) and also their 2.80, that'll add a couple of lbs of boost (some see as much as 3 more lbs)
As for the performance improvement, YOU WILL DEF NOTICE IT IMMEDIATLY,
and you will also notice that SOB will give you boost faster, (LIKE INSTANTLY)
Uppers are known for that (even know many disagree, it's a fact jack)
As for belts, you can run both on the stock belt
As for how small you can go, Terry (SFPH) South Florida Pulley Headquarters is a Vendor here, and DEF the Upper Pulley Man (after all, he invented the first for the L)
and the first for pretty much every other S/C out there
http://www.southfloridapulleyhq.com/
http://www.southfloridapulleyhq.com/SFPH/lightning/ps_dub_nonslip_system.htm
He now offers a new Hub and Pulley set up that will allow 2.6, 2.8, 2.93, + 3.10
Anything less than 2.8 on a Eaton, and you will have to file down the ribs a little,
but it's a very easy job, and not much has to be filed
I just happen to have a ported Eaton WITH the SFPH set up on it, that I soon will not be using, I got me a Magnum Powers Supercharger now

but I think Josh is buying the Pulley set up ???
Plenty of info there on his site, or copy your post and put it in the Vendor Section and Terry will DEF answer you right away
His Sec is here
http://www.lightningrodder.com/forum/index.php?board=33.0