Hi dirt, I've been looking for performance parts for the HS35 and really haven't found anything. There are some header kits that look good you may consider if you can weld, tig welding the header is best, unless you are real proficent with a mig and can weld without burning through. It's all about flow, If you burn through and leave a bunch of bodaggets in there's not much point. I also reccomend a stepped header. You will have a better overall power curve, more bottom end torque, and more top end. A reverse megaphone into a muffler usually show big gains too. If you don't have welding capabilities you can get a header kit, cut and mark your parts, then take them to a welder. I'm a fabricator, and have an HS35 engine here. If you really want one pm me and we could discuss a custom stepped header, or a real basic cheaper one. Good luck:grind: