I get the countershaft sprockets from Superior Sprockets in Oregon, rear sprockets from Vortex, and I cant remember who I get the chains from. If somebody is serious about doing a 520 conversion let me know and I will get part numbers and everything you need to do this. For those of you who dont know Brenda Sue made the fastest NA runs, on pavement, on my bike this year. Larry Forstall's Guppy made the fastest NA run ever, at Bonneville, wiwth a 520 chain.