What is the Difference?

[GT2000]

....in lap times between Q500 424 (ie a standard class Q500 with stock .40 or .46 motors) and 428 using proper Q500 motors?

[DLD]

I think you'll find about 3 seconds a lap difference. 428s do about 1 minute for ten laps, 424 about 1 1/2 minutes, roughly.

David Layne

[mrbcruzn]

Our club is going to run a AMA 424 this summer and to our best knowledge the only engine that has been approved is the Thunder Tiger .40 pro for this race. The 428 has not requirement on brands and you don't have to use stock mufflers etc.