A lot of people will recommend a turbo or efi, but seeing how you are new to motors and whatnot, I'd avoid it like the plague. A mild build will even require a lot of studying to get everything matched right. Don't just go slapping a lot of different parts together, everything needs to be matched. It's like a puzzle. And personally, for a mild street motor I wouldn't be too worried about balancing even. Just my 2 cents.