ORIGINAL: Konrad

OK, A baffle engine should actually run a little more economically for the same power. This is because the hot baffle should aid in the atomization of the fuel. Also at less than optimum tune (RPM) less fuel should go straight out the exhaust. Now a real down side to the baffle engine is that in the combustion chamber it (the baffle) blocks (obstructs) about a third of the piston face from providing much power at the critical first 15° after top dead center. PDP helps scavenge the dead spot on the exhaust side of the baffle. This allows for a more powerful burn in the combustion chamber.

The Perry carb was great in its day. It does have a tendency to run rich in the mid range. If you are going to go with the bother of a pump do place the tank at the CofG and use what is known a pump carb (large bore) I like some of the carbs that were designed for pattern work. These often had a means to adjust that mid range (often needed to bring the engine on pipe) The also often had an in flight mixture control For richening to mixture once the engine was on pipe. Since you are asking I assume you haven't used a real pattern engine. I strongly recommend that you work up to a full blown pattern engine slowly. No pumps for your first piped engine. A small carb for your first piped engine.

I liked the 12 ounce tank as I did like to loiter around much (fly land refuel and do it again). Loitering costs money!

All the best,

Konrad

P,S.
That first picture is of my Webra long stroke sporting the Perry pump she is showing you where the pump should be placed for optimum performance. She is also in sport trim as she has a ringed P&L set. She also has a carb with an accelerator pump and in flight fuel mixture controls. The two rear exhaust engines also are showing the in flight mixture control, I hope in more detail. By the way I think the CMB 60 was the pinnacle of the short stroke engine Yes I liked the YS 60 but she needed a new set of ABC P&Ls to really last a season of hard practice and competition. Performance Specialties had these ABC P&Ls for sale in the heyday of the YS.

Please note there are no OSs in my collection there are very good reasons for this. They might be an adequate sport engine but under the stress of competition a stock OS can't cut it. Now OS did later make a hand assembled engine from selected parts that was workable again with some rework like the YS 60. It was called the Hanno. Now with that having been said the OS FSR was a great sport work horse that might fit your needs.