RE: MagnumR dolly
On a modern model engine, with very few exceptions, the only thing that causes a plug to blow is a lean run. This can be either from setting the engine too lean for launch, or can be caused by an air leak somewhere causing air bubbles in the fuel, or foam in the fuel caused by airframe vibration.
Remember, a piped engine will require more fuel when it unloads in the air, and should always be launched slightly rich to accomdate this.
If you are getting a good needle on the ground, are certain you have no fuel system leaks, and are launching rich........ and the engine still goes lean and blows plugs in the air...... the culpret is fuel foam. I would first make sure the fuel tank is properly padded and not touching any airframe structure.
What aircraft is it installed in ??