Is this on dirt or pavement ?
It sounds to me that you are a newby to circle track racing. Stay with a bone stock and totally reliable and consistent 350 and LEARN HOW to race. It's just natural to build a 'competitive' engine and go slay the dragons when you first start out, but it ain't gonna happen, kiddo. The learning curve is steep and you need your basic racing skills sharpened BEFORE you go hunting those dragons. Been there, done that, got lots of T shirts ! Driving a smooth and consistent line is a LOT more faster than uncontrolled horsepower. You do the above and you'll not get disappointed and quit because you are frustrated with not finishing well or breaking stuff.
Remember, racing is all about FUN, when it stops being fun, it's time to change something.