They actually tune very well with both the 7 and 8 mm venturis. You do gain about 45 sec in truggy with the 7mm but the 8mm gives more power and top end.

Also these engines like to run in the 250-260 range On a hot 90+ deg day race tuned. I see guys trying to keep them at 220 or so and ther runtimes and power is down big time. This engine has so much power that some people are leaving them on the rich side. But on an optimal tune with the proper temps thats where the mileage and rediculous power is at.

Thanks,
Lance
RcRenew