a while ago i bought a sk27cc motor to put in my 1/4 scale car. stock it came with 3.5hp on gas. since then i've added a filter, tuned pipe, bigger carb, raised the compression, a billet head, and converted it to alcohol. im running 5%oil, 10% propylene oxide, 5% nitro, and 80% alcohol fuel. i'd have to say it putting out double the stock hp, 7 hp. my question is how much can it make? whats the weak link in these motors? thanks for lookin...PB