Whats the best big bore kit for the raptor 660? What kit makes good power and is still reliable?

 

I don't know for sure, but am looking into the same thing, and it seems like sparks, craycraft, and kenz is the way to go.

 

There is also Robertson Cycle in Omaha, NE. 402 339 1814 ask for Mark Robertson. I've been running my 77-82 H.P. @ 10,000 Rpm Raptor for 2 years without a problem.
Check my gallery page to see his work. In Fact he just finished a Big Bore Raptor that is pushing the same HP as mine for a guy in Kansas. Good luck with whoever you choose,
Kenz, Sparks and Craycraft are good builders.

 

yeah dont forget roberston he had been make HUGE power on the raptors lately..Hate of to him. i would keep it in the 686 range though to maintain reliablity.