I've added our 350x Big Bores to the list of offerings! I've wanted to make more of these for a loooong time. Custom high strength cast iron sleeve machined into a factory 350x cylinder. Fast revving, lightened, gas ported, 11.5:1* compression CP piston. I sold out of my first run of 10 in less then 12 hours. Price on these is going to be $650 shipped, plus a core cylinder. The kit is 100% bolt on. No case mods needed. It is a true 400cc's.