Jerry,

The 46 weighs slightly less than the 40 which may be a slight advantage.  The 46 must be flown with ,018 lines vs .15 for the 40. which may be a slight disadvantage.  I'm putting a .40 on my Cardinal.  I live slightly above sea level and the 40 is more than enough power.  You should be able to increase your nitro a little and use a higher pitched prop and make out fine with the 40.  From some of your past posts I know you were using a 9x5 on your la .25 where I use a 9x4 for a similar weight plane.  I just bought a pack of 11x4 props for my LA .40s and use 10% nitro and 22% oil (50/50).

I think you ought to try the 40 in the interest of science.    Let us know how it goes.  I must have missed the bad things said about the 40 maybe it's because I have so many of them.    Since the 40 and 46 use the same mounting holes you could try it on the plane you already have.

Tom & Dennis, thanks for reinforcing my thoughts that both engines should both be  similar in user friendly performance.
I plan to put the .40 in a profile Oriental which just needs covering and painting.
My choice in props and nitro is dictated by my altitude (5000'). Probably nitro more than prop. When I had some problems with engine run a few years ago, Bret Buck e-maild me and suggested the higher nitro(I was using 10%), even suggested trying 20% nitro if the 15% didn't work. The 15% worked just fine. My choice of props was based on how my slighty heavy Barnstormer (OS.25LA) flew after testing various props. Pehaps a 10x4 would have worked good if I had built a bit lighter. Don't know why but a choice of a 5 pitch prop no matter who the mfg. is seems to dial all my engines in to the right speed and perfomance.

Ron, Thanks for sharing youe experience. Bummer you have 4 fishing sinkers.
Now if we can find out why Tom and Dennis had good luck and you very poor.
Anybody out there care to guess why the diffrence?
Fuel, tank type or plug diffrences, atmosperic diffrences or just plain bad batch of 4.

Ron,
Sorry.  It IS just a .40 (the piston & liner from a LA 46 are too big in diameter to fit in the LA 40 case).
I think the APC prop is one of the major reasons my LA 40 runs so well. I do not try to slow the engine down. I let it run fast. Because of the relatively low pitch of the APC 10.5 x 4.5 prop the plane flies at a reasonable speed. When my engine is first started, it is needled so it sounds like it is running in a wet 2 cycle. However, as I start to walk out to the handle the engine has warmed up and I can hear it "kick in" to a lean 2 cycle full song scream. The engine does not run away during the flight because it is already running wide open.
I enjoyed watching your electric "Shocker" fly at FCM. Hope we get to see more of it.
Dennis