Quote:
Originally Posted by coolcoupe
I have totally forgot what the benefit of the pennies was and does it need to steel pennies ?
|
Cool coupe, long story here. Heat risers help vaporize the fuel when the engine is cold. Makes for a quicker warmup. A side effect of these heat risers is that they connect the two exhaust systems directly, going through the intake manifold, thereby buffering each other’s noise level. Pennies are sized perfectly to tap into the holes in the block under the manifold, and don’t interfere with the gasket, as is possible if shim stock is used. Wheatstalk pennies are of a good alloy for the purpose, not causing electrolysis. Guys used to select pennies from the year of their birth for the heck of it, and the 1943 steel pennies should work as well. Modern pennies not so well, not a good alloy. Two reasons for blocking heat risers. One, the flathead exhaust rap is accentuated, which brings a smile to my face, and two, blocking these ports helps dump heat directly to the exhaust rather than saturating the manifold with excess heat.