Maurice,

Should work without problem. You may still be able to find the venturii and needle valve assembly at Tower. If not there are some 3rd party "cottage" guys who can supply the pieces.

Depending on what type of CL flying you'd like to do, the FP has served well. For some, box-stock (other than the venturii/NVA change) worked well. For more serious "stunt" CLPA fliers, there were various mods. There are many good CL fliers in Eastern NJ, btw.

If a manufacturer produces the same engine in CL/FF and RC versions, often, the CL/FF versions are identical to the RC version, except for a venturii/NVA in place of a throttle. For CL Stunt, engines like the 40-FP have done well with mods as simple as one or two added head gaskets.

The "Classic" 4 cycle/ 2 cycle "stunt" run mode always sounds good, but so many "modern" (i.e., ABC or equivalent, Schenurle-ported) engines are primarily designed for the higher RPM RC use. You would lose too much power running them around 9,500-10,000 RPM to get that sound. The answer has often come down to running a slightly larger, flatter pitch prop to get nearer the engine's best power range and still keep airspeed (thus laptime) manageable.

Recommended prop for RC with a 40-FP RC version is something like a 10-6; for comfortable CL use an 11-4 or 11-5 lets it rev to its comfort zone, and doesn't spin you dizzy on 60+foot lines.

Another few things have worked reliably: a fairly hot plug, 10% nitro, 11% each castor and synthetic oil fuel, and muffler pressure to the tank. BTW, the huge stock muffler can be replaced by a much smaller, lighter "chip" or "tongue" type. These look like the extension neck on the stock mufflers, capped at the outer end and drilled with many small holes to let the hot gases out. They reduced sound well, if not as well as the big trashcans, and can provide muffler pressure for the tank.

The run setting should be a "wet 2-cycle" - smooth, steady 2-cycling, but not peaked out. Definitely visible exhaust "vapors." In stunt, maneuver airloads caused the firing mode shift from 4- to 2-cycle in the older iron piston/steel sleeve, baffle piston engines. If things went right, you heard a 4 cycle purr and a 2 cycle shriek as maneuvers loaded the engine. With a "wet 2-cycle" run, there's little audible change in engine sound.

You start to think there's no RPM change. (I still think there is, but we can't discern it as easily. It isn't the sound of firing every other revolution then shifting to firing every time as in the traditional 4/2 style run.)

If you can find the Joisey control-line guys, they can help you a lot...

Luck!