Have a 73 stingray with the 5.7, considering changing the manifold and the carb to Edelbrock with 750 cfm. Anyone have any experience or information with this combination? will it work?

It will work, just kinda depends on how stock your engine is as to how much 'performance' you will get.  Dad's 76 vette, has a 750 Edlebrock and it works rather well,  only issue as of the last time driven(its been a few years now) is that on "HARD" acceleration from a stop, is that sometimes (what was explained to me anyhow) the floats will stick, and basically dry the bowl before shuddering and letting the fuel pump refill the carb.... and that has happened to me several times on the drag strip(fun running)with my 78(running a 650 cfm Edlebrock)  

thanks, trying to decide whether to go back to Q-jet or move on to something new.

IMHO, the Q-jet is hard to beat as a performance carb, especially for a SBC.  Easy to maintain, tune, and provides all the air and fuel the SBC needs.