Mine stalls @ 5600 and goes out the back at 7200. I am running a 10.5 X 30 Hoosier radial. They measure 29.5" tall. Rear is a Dana with 4.10's. The tires may sound kind of small, but my wheel wells are stock. Since I switched to ladder bars traction issues are a thing of the past. The trap Rpm's are higher than yours. Probably because radials don't grow like bias ply's. Before my timing chain let go this summer ran a best of 148 mph. Was looking forward to a new best this fall but, the motor had to come apart to retrieve missing chain links. Been to busy with work and life to get MONTESSA back together. Well, I guess that I have all winter now!