Does anyone know the minimum octane number that the following crate engines need? $1299 190 hp and $2099 330 hp (prices are estimates) I would like more power than 190hp. What else do you need to buy with the 330hp? I have TH350 with NP203. If the gas is 91 octane I'll probably stick with the 190hp motor. I can't afford these gas prices. One more question. Is the intake manifold for the 190hp stock or a GM performance model?