This bike was clocked at 131 mph on run at the Bonneville BUB meet last year. The fastest LSR speed by a naked frame modified Triumph 650 on gas.It's in altered class allowing very low seating which should help top speed . It has a Triumph 2 valve head and pre unit cases. I have discussed engines with this guy (Astek racing)....The engine has short intakes, about three inches. When I asked him about the long exhaust he said it was chosen because it looks "cool". He's a bit secretive about the engine build but claims the engine has never seen a dyno, the bike has no tachometer. My guess it about 7500 rpm to make the power needed?
This was Tim Joyce's race bike,or one of them. Very highly modified of course and a 750 ...Notice the intake length and exhaust length. 8500 rpm?
Circuit racing is far different than LSR racing but I'm thinking Tim's bike will run quite fast on top end at an LSR track.
I think these examples show relationship between exhaust and intake lengths