i am 6'4'' as well, but i am only 190 lbs.. i would say that heavier guys should prolly lean towards a 4 poke.. the power band is much more suited towards supporting ur weight, and you will have alot more fun with that then havin to chase gears all the time on a 2 stroke... i think that the machine you should really look into would be a grizzly, they are pretty fast and would support ur size much better performance and comfort wise...