I think you will be happy with the 66cc for power. I have a 44 t sprocket and wish I had a larger one due to the speed required to hit the powerband. Users on this forum have cautioned me against using the 54 t saying a few more teeth makes a bigger difference than I think so I'm going to play around a bit with sprockets.
I personally don't mind having a few different size sprockets as I plan on doing several builds with the hope of selling some. I'm more into power than speed. I do not regret my purchase this is a fun hobby for both building and riding.
Also I think your front tube might require a larger adapter than what came in my stock kit so keep that in mind. I don't know what kit you are buying with your engine.
To me (the newb) your frame looks like it might be ok, you need 11" from the bottom of the top tube the top of the barrel of the crank. See the sizing image on the kit on the link below.