id say your top speed for ur 440 is about right 80mph....however i would not recomend running it at top for that long...other than my 600 triple indy...i have a 04 arctic cat 440lx....i ran it at top and blew the engine...because my 440 and your 440 are both single piped so it doesnt have much to rely on but that single pipe when going full speed...becarful
