Shakespeare never had to a chance to modify an engine, but the question is a valid one. Sometimes we make decisions based on bad information and I must plead “guilty”! There are racing products that make good choices in our street driven Mustangs, but sometimes we go overboard. A great example is exhaust headers. HEAT is a very big problem for a street engine that must deal with stop-and-go traffic, long periods of idling, running the air conditioner and maybe even climbing mountain roads with thin air and steep inclines. Headers can make things worse!

A good cooling system is a MUST in our SIX so give it plenty of attention to save your motor. A good radiator, fan, tight belts, proper anti-freeze level, good water pump and hoses can keep you on the road rather than sitting waiting for a tow-truck! Watching the temp gauge, especially in hot weather, should always be part of our driving habits…but sometimes we get caught up in the fun of the moment and forget. Pay attention! But what do headers have to do with an overheated motor? Plenty!

The next time you get a chance to look at a SIX with headers notice how much more surface area they present to the engine compartment. Then look at the factory cast iron manifold. Headers were designed for racing where speed usually removed that heat quickly, and the free-flowing exhaust was more important for making power. If trapped heat became a problem radical modifications could be made to the hood or front fenders to exhaust that heat. Heat is energy so sometimes keeping things hot was desired! Besides, the engine was going to be rebuilt or changed before the next race! I don’t want to rebuild my engine before each Mustang gathering, so keeping heat to a minimum is desired.

Headers work well to accomplish getting burnt gasses out of the engine but those gasses are very hot. They can turn the header pipes cherry read and that heat is in an engine compartment where the carburetor sits directly over the exhaust. That can be disastrous! Here in Texas heat is a serious problem for our SIX, and coupled with ethanol gas it becomes doubly bad! I have watched my 1100 Autolite percolate fuel into the venturi of the carb due to heat. Not vapor-lock, “percolation”…like an old coffee pot percolator. That is just one problem caused by excessive under-hood heat and today’s gas.

The factory cast iron manifold can be improved without increasing under-hood heat and still give us improved exhaust flow. Using wide masking tape, make a template to match the exhaust ports to the manifold. With the exhaust off and tape over the head ports, cut the openings out, then peel the tape carefully off the head. Now you have a template of the exhaust port position and size. Lay the template on the exhaust manifold and mark the areas where material needs to be removed to match the head ports. With a small grinder the exhaust manifold can be “matched” to the head for a perfect flow with less turbulence. Those middle port “dividers” have not been shown to improve flow and can rattle!

This can be done to a concourse car also because you are simply improving the “fit” of OEM parts. Before the days of many after-market parts sources, we “modified by matching” stock parts for best fit. The intake ports-to-head, exhaust ports-to-manifold, water pump-to-block, carb-to-intake and any place where matching would improve flow. Air, oil, water, gas and exhaust flow improvements can greatly improve how our little SIX performs, without installing unnecessary speed-equipment that costs $$ and can create more problems than they solve. For those who already have headers, wrap them with a heat-barrier if heat becomes a problem. I LOVE HEADERS, but not always on a daily driver! Stay safe SIXERS!

Charles Johns “Geezer” Rising Star, Texas


Posted in Old School Old Geezer