Hi Sledge - I have a QF 750 CFM carb on the 393 in my Lone Star Cobra Replica and also on the 383 in my wife's '67 Nova. Started having issues with the engine in the Nova doing what I suspected to be vapor locking on a regular basis. Pulled my hair trying to find solutions and after some research, I found that Quick Fuel made what they call their Quick Cool Carburetor Insulator Kit.
The main insulator plate consists of a poly material sandwiched between two thin sheets of aluminum. The cost was a little less than $100 so I ordered one, installed it on her 383 and we've not had a single issue since and that was four years ago.
Since Holley purchased Quick Fuel, I wondered if they still made the insulator kit. Looked up my four year old part number, found that although the part number had changed Summit Racing does carry it. Hopefully the following link works for you but if not, the part number is 300-4013QFT.
https://www.summitracing.com/int/parts/qft-300-4013qft