K-man,
While the os .46ax is a very good engine it is way more than you need on a falcon 56.it is over 1.5 h.p which is what the .60 of the day could only hope to produce.I built my falcon in 1970 when I was 15,power was an os s 35 it was covered in silk and dope and had airlerons,used a Kraft series 70 4 channel with kps-11 linear servos weighed 5 1/2 pounds.took me 1 1/2 years of lawn cutting and snow shoveling to buy everything radio was $320 back then.after I had soloed I replaced the os 35 with a os h 40 p that produced a little over 1 hp used an 11-6 prop vs the 10-6 and flew that plane for 2 years before I could save up for a vk cherokee in 1972. That falcon could do almost any manuever except knife edge.if it was lighter a smaller engine would have been fine.I still have it the airframe itself is still airworthy but the silk covering has dry rotted and it needs to be recovered.Good Luck