May I suggest the GCBM R/C 25cc conversion engine. 2.4 horsepower, swings a 16X8 @ 8,600 rpm, 18X8 @ 7,200 rpm, super reliable Homelite core engine, magneto flywheel, slightly lighter than the 38's, and much lighter on the wallet @ $210.00 a pop.
Regards,
GPB
www.gcbmrc.com