Intake manifold choices

less typing and more wrenching will fix this. Install the carb heat insulator, plumb the return line and bypass reg and you will end this problem. I use a $40 holley regulator and it works great. Rock steady 6.5 psi set at the factory. After adding a return system all my hot start issues ended. I have always run an airgap. I'm in Florida with brutal summer temps. The upper radiator hose can cook the front bowl so insulation around the thermostat housing and hose also helps.