Khalid: No heat riser port,on E/Q heads... My LA bolt pattern heads,still had a sealed heat riser crossover port...Isn't gonna happen... The heater under the plenum,is interesting...In the 80's,some OEM carbed setups,used "heat grid " gaskets.. Electrical controlled,would preheat the air/fuel mixture for emulsification...Not aware ,of an four barrel application,just some info.