We raced in the 410 class with our sprint car and picked up some pointers on the sb400. First was block selection, forget the one with three freeze plugs---thin decks and heat problems. The block with the two freeze plugs and boss for the third one is acceptable but still not the best. The block that has two and looks like any other sbc is the one to use. Also 6" rods for good geometry and Mallory metal in counter weights for internal balance. All told an expensive engine to build but would run at the front of the pack. Sprint cars run no fan and small radiator so heat was controlled with alcohol fuel. Richer the mixture the more heat carried out the exhaust plus driver could kill mag at end of straight a way for instinct cylinder cooling. On ANY car the exhaust gets rid of 85% of the heat and radiator 15%.
