Bug juice made about 25 4.1x or so passes last year... this year we put on some better heads.. but haven't had time to get it on the dyno .. that's in the winter plans...I expect it to run in the 4.0 range if not a bit faster once we get it set up right... the same for the bike I just got. its a tad lighter, has a bit more compression, and has a bit bigger valves... with newer/ different BK drag pipe... I have no idea if, or what more power it makes.. I just got the dyno set up at the new shop Sunday.
its a dirt track... and it is what it is... No reason to get into all that noise... I think he ran a 4.07 once @ 76 mph or so.... Kind of impossible to compare a long parted out bike to stuff running today. About the only thing I know to do is load up the trailer next year and go to sheltons ourselves and see whats it about.
We have some of Mac on the Battenfelder facebook site. Our track is about 0.5 second slow due to altitude and traction. He ran an R1 powered moly framed bike in the final and red lighted out. In an earlier race he beat the R1 by .01 with a bike time of 4.4 so I could see him under 4.0 on a better prepared track.