Next mod is the bearing seals. One thing we did when we raced RC nitro cars was to remove the interior bearing shields or seals to reduce drag. The front bearing outer seal is left intact and for this one I'm also leaving the inside seal. The main bearing will not have any seals. I want to see if there's any leaking from the front seal after some running. If not I can take out the inner front bearing seal and check again.

Back cover mod: The back cover helps reduce the volume of the crank case. That's great but it's also not optimized for flow. I'm going to port the cover to favor the engines natural direction and suction on the power stroke. I'll post a pic on this later. The idea here is to improve flow to the transfer port when the charge should be at its highest velocity. The port opening has very sharp square edges. I'll be adding a radius and smoothing the edges.

Next up are the gaskets. If you dry assemble the head with the gasket to the case you will clearly see the gasket edges encroach on the ports. This has to be port matched. This has to be done on the intake too.

Then theres the dreaded intake reeds. This wasn't done before I was given the engine so I'll be blueprinting the reed block and making sure the reeds seat tightly to the surfaces.

Why am I bothering with all this?
The regular 20 engine powered a TF 60 size P-51 to 109mph with an APC 16x10 prop. I want to go faster!! I want to see 120mph! So I'm switching to the RA which has better performance normally but I'm making it better than stock. We shall see..,

Thats it for for now on this little beast. Please post about your engine mods and results so we can learn and improve these engines.