did anyone install a sparks rev box??

[cals400ex]

i was wondering if anyone installed the sparks rev box. my friend got a little top speed out his. i don't understand this: he has big gun slip on, K&N filter, sparks timing key, and sparks rev box. he is jetted with a 152 keihin mainjet. i have a complete stainless sparks x-6, no air box lid, uni filter, and i went two teeth down on the rear sprocket. i run a 158 keihin main jet. he pulls on me pretty good once we get into fifth gear. i dont understand this crap. i was going to try a sparks rev box because i know it gave him a little more top speed because he beats me worse now up top than before he put it on. i was always told that the rev boxes were junk unless your engine was built. the white brothers may be, i don't know. this sparks one did give a small gain up top. any suggestions

[mx400]

well i will let you know in a couple of days when my box gets here. ordered it today and plan on putting it on the day it gets here

[norcalatver]

Try going down on your main jet. You are probably running too rich. If you are running rich it affects the top end.

[cals400ex]

yeah, i already went down to a 155 main to see if that was better. i have not raced him yet, but my butt-o-meter couldn't tell any difference between the 158 and 155. let me know what you think of the box when you get it in.