I would think 124 mph would be upper 10`s and as far as where to start, you may be visiting the track a few times to figure that out. If you can, chassis tune that puppy first and get the afr`s close to save a bunch of money and time or even damage if its lean. Then start w/ proper tire pressures, leave rpm`s and shift points.....then of course there`s shock settings, squirteres, final jetting etc. Get the idea?