I haven't had a 65 LA engine, but yrs ago had a 60 FP which was the predecessor and also had plain bushing type bearing in the crankcase.  It was annemic at something like 1.4 hp (compared to the 65 LA with 1.7 hp).  I had it installed in a E-Z P-51 Dallas Doll from Hobby Shack (People).  

Since it wouldn't make much power, I decided to check the port timing.  It was very much lower than the ball bearing 61 O.S. engines and other normal to high output engines.  I decided to port the sleeve to change the timing to match my Rossi 40.  I changed both the intake and exhaust timing to the same as the Rossi using a degree wheel (protractor) to measure it.  Then I installed a Mac tuned pipe w/muffler and header.  I tuned the headpipe length for max output.  The engine really came alive.  Albeit the carburetor and bore of the crankshaft were smaller than the 61 Max, that engine put out almost as much as a 61 with a tuned pipe.  That engine also gave many many reliable hrs of flying.

I relate the story above because I'm a believer in plain bearing (bushing) airplane engines for sport flying.  I've had so many ball bearing engines rust up the bearings even after care flushing and lubing with after run oils etc.</p>

I think the 65 LA should be a real powerhouse with some port timing changes and a tuned pipe.  I think I'll get one for my next p-51.  </p>

Chuck</p>