Sounds like you pissed a lot of money away on crap. Which is why it is important to be an educated consumer (I hope other can read this example and take it as a lesson learned).
As already stated, your pistons are most likely in the hole .040" or more, you're probably running a .045" gasket, you have some of the worst heads ever produced by chevy, and one of the laziest cams still sold (with WAY too much seat duration). If you tried to sell that engine you could probably only get about $250 for it as there is literally nothing of value in it.
At this point the easiest/cheapest way out IMO is to buy a used running Vortec or LT1 engine, do a intake/dizzy swap, keep your carb, and sell your engine off to someone who just needs a running sbc for a daily driver.
A second option is to run a "mini-blower" and a cam swap with about 7psi but that will end up costing twice as much as the option I outlined.