How to 360?

Well with the added info. I would definitely keep the LD340, it is a very good street intake. I went from a Performer to a LD340 and man what a difference!
I agree the 650 Dp is a good carb and will give you crisper throttle response, you may lose a little on the top end. Work on bumping the compression up. Easiest way is to mill the heads and use a good MLS .027 head gasket. I would spend your money on a cam and kit. I'm a Hughes Engine cam supporter, thou some will disagree. I might use they're HEH2328AL.