Stu, I have three engines that will fit this model:
Saito 1.5
Magnum 41 (USA 2.5)
Zenoah G-62

I’ve ruled out the saito because I’ve been told it will muck up the paint. The 41 is the presently leading candidate after hearing what
Fofly had to say, and assuming I will need some nose weight. The G-62 will make it hum but not leave much cowl. I’m looking for all the 1nput I can get here to help make up my mind.

As for CJ retracts I have 7 pair Rhom-Air, 3 pair Spring Air, and three pair CJ. Every spring I add 2 or 3 drops of AC leak stop to each set and have never had a problem. I have one set of CJ’s that have 250 flights on them with no problems. Well except when the OLEO strut adapter breaks about every 100 flights. Getting the part from the local tool & model shop was much more timely.

My son Bought retracts for a flop tite P-40 and both cylinders leak still.

I bought the FW retracts and the deployed side does not have a over center lock so under side load the cylinder while amplified by the inclined plane must resist the load. After sending Bruce drawings on how to fix it on two occasions I never got a response. So back to the local tool and modeling shop and you have seen the pictures.

Joe