The dist in a Chevy runs clockwise. Pull the left valvecover and rotate the crank until you see the intake valve open then close, then align your timing marks. This will make sure your on the compression stroke. You sayyou just put a new cam in it? Are you positive the timing marks on the sprockets are aligned?

What exactly is it doing? Spitting out the carb, popping out the exhaust?

Hope this helps.