Hi.

I've been in contact with Hot Bodies D8 / HPI Pro driver John Holmes from England. He was the test pilot on that engine, and has been racing them for a year now. Here is the setup he is running:

Stock engine.

Stock shims.

HPI R8 plug.
(He is very impressed with those plugs, and I'm going to try them for sure ) R8 are cold and R7 are warmer.

Stock 8 mm venturi.

Running 30% Optifuel.

JP-4 pipe.

Very fast on the straight and enough bottom.

About 9 min runtime.

John:
"I have been using them for a year now I was the test pilot,the components are very good for lasting , just replaced a couple of bearings due to running engine in very wet weather but other than that no problems"