I have been riding a custom built 850 ultra engine for years now. in my old style wedge, it will spank the $#!% out of my buddys '02 700, and his '10 800 dragon. it doesn't handle as well, but I'm telling you, that is one tough engine to beat when you have the ability to tune it. Mine has PSI mod blaster pipes, Heads, "Big Air" carbs (cause its a never ending tuning battle...LOL!) and stage 5 PSI porting. The chassis is a custom bulkhead, Van Amburg tunnel, 144" track, and Holtz suspension all the way around. I love this sled, but Im going to try that engine in an '06 dragon chassis to see what happens.