If you can.get the S7 Europa cheap, use it, get away from the JP pipe, they tend to run hotter than most pipes, the Europa was the same engine, piston, sleeve, rod, and crank as the WS7, what was different, was the crank was not coated, the case was not black, and the rod was not as good, I probably went thru a half a dozen over the years when they were around, use the RB 2045 pipe, with the RB198 header, it will give you plenty of bottom, maybe even use the RB 204 header, it will.give you more bottom yet. It would probably be best to replace the conrod in that engine also, if your using the engine in a truggy, go with all aluminum clutch shoes too, it should be fine.