your galaxy is a 2547 right? thats a single final radio (you can make them a duel final pretty easy. the 3900 gold's are a duel final (at least the brand new ones are) so yo will gain some power, 25 watts on ssb and 5-9 watts on am.
what are you trying to drive? most solid state amps need a much lower drive, say 1-3 watts unless they are using a 2879 transistor, they can handle a bit more, say under 20. older tube amps dont like alot of drive either, that Courier is a great driver for a larger amp, they do about 125 or so peak