Just had two of our war bird guys get new FPE engines, 5.8. Very well made, run strong, use sachs cylinder and pistons and rods. one piece custom made crank. The engines are very beefy and comparable to Brisons in every way. The Fox is very similar. Looks like either would be a straight replacement for the Brisons. They also make 4.2 engines similar to the Brison.
Larry