Thank you for the input guys.
Sparky sure I am interested with both TT .46. By the way, how long after you race TT engine then notice the reduction in power ?
what prop do you run with them for 424 class ? 9x6 ? what fuel and at what RPM does it run ?
I haven't try any prop lighter than 9x7. If I remember Correctly, 9x7 run about 16500, 9x7.5 16000, 9x8 15500ish.
So far 9x8 seems to be fastest.

Greg, we are only allowed ASP, TT, SuperTigre and OS as the engine, all with carburator, the engine must be race as is out of the box.
I might be able to use the Jett for practice, how about using carb, and limit the throtle barrel to similar OS RPM and using same prop ?