KE55

Hi all, nice site, I have recently picked up a stocko ke55 sedan off ebay, it is dual fuel and I have got it regoed (it only cost me $165 off ebay) its a 5 speed with air con. things ive discovered: misses on number four after 3-5 minutes of warming up. headgasket? sticky valve? when i take off or compression brake i hear a clunk and the steering changes, I'm guessing the pivot bush on the rear springs needs replacing, at least one side needs it. i am wanting to do something about power upgrade without having to get it engineered, or rego changes. it handles like a dog atm, anything to stiffen it up would be great, so I'm basically asking advice or how too's thanks all ben :)