You are right of course. All heavy duty Diesels have inter-coolers between the turbo and intake for that reason. I wish I had blocked the heat risers to the intake when I built the car. I have also ordered and received a phenolic 1/2 inch spacer to put under the carb which I hope will help. I drove the car for a good while before I painted the hood. I can really tell a differance when it gets warm on a hot day. It doesn't overheat. Just really has a power drop.