Back in the late 80's when I used to ride a hopped up Honda 250R in the dunes, I raced quite a few LT250r's. It seemed like the Hondas always had the edge in the motor dept. I know they made stroker cranks for them but I'm not sure who. You can try Falicon, they can probably still make you one (727-797-2468).
I never got beat by an LT250R but I'm sure somebody out there had something really fast (There's always somebody faster). Reliability wise, I only heard negative things about the hopped up Quadzillas, especially the 87's. They had one less head stud and seemed to pop frequently.
Steve