For those that don't know what the old Royal Radial looked like, here are some pictures. It does not have the rocker arm housings, I added those by cutting a balsa stick in about 1/4" sections and gluing them on. Lightly sanded and painted you can then use 1/8" plastic tube for the push-rods. Of course you know that the engine should be mounted to a sheet of 1/8" ply. The last picture is the radial I painted.

Dion