Dual shocks on the rear were a not too uncommon mod. Easy to do and it handled the weight better. The primary clutch looks like a Salsbury 815/816. Aluminum hub - 815, steel hub - 816. I'm not sure why it has 2 sprockets on the jackshaft but they look different, maybe a 9 and a 10t for a quick change. That thing is gonna have a load of power. Piped 340as engines are in the 50hp range. These things get you from 0 to holy crap in just a couple seconds. Been there done that!