depending on who you talk to, you do/don't need the 18lb springs when you remove the gov'na. why would you replace the pushrods? unless you are adding a bigger carb, cam, raising the compression significantly or advancing your timing, you do not need to upgrade the rod or fly. a header and better flowing airfilter are the cheapest easiest power upgrades. you will probably have to re-jet the carb when you swap out the air filter. the 140 emulsion tube will help you on bottom and mid range. or you could experiment and seal over one or two holes in your own e-tube to achieve the same. if you have the thick head gasket, switch to the thinner ones. it will give you more torque. if i am not mistaken, compression=torque, flow=speed. you are geared for speed so add some torque. if i am wrong, others will correct.