RE: Which Q500 engine to buy
@ Smitty
yes venturi as offered from Shadel for the Q500 FAI fuel version. Before the FAI fuel Q500 version with the 12.5mm gas passage and different head became available we had been simply using the same engine as in the US, but replaced the throttle valve with the 11mm venturi from the Q40 engines. This "version" is still been used by most. But venturi is not a must. In our rules there is no limit to the intake and exhaust outlet size. So having the larger intake was the main intense. (11mm venturi +11mm gas passage).