i have never seen a 3 port being able to hang with a 5 port. unless you were talking about a no brand, cheap 5 port versus a nova 3 port. but the fx is a nova based engine and modified by one of the best modifiers in the world, so to hang with that engine, i would definitely go with a 5 port modified engine. i would say a murnan mod engine and also you can pm him on this forum and ask him what the best solution to your situation would be. his screenname is grinder. he will hook you up, good guy and fast engines.
Thanks for the info joemugen I sent grinder a message