I'm not familiar with a 4655. I think it would have the newer style valves that just use one wire to turn them on and off. If that's the case, it's not very hard to add an EZ-Boom. How many sections on your booms?
I replaced a Raven 440 and added four sections to my Coupe to make it seven sections. Really not much to it, as the Raven plug fit right into the EZ-Boom. We did add some more contacts to the plug to access the extra sections but all the rest worked and we used the old flowmeter and flow control valve by just entering the correct values into the 500.