A friend of mine, my brother, and myself worked on that 390 by having the heads rebuilt for more performance, and a cam put in for the same reason. Problem was we were stupid kids, the engine had 220,000 miles on it, but ran good, but with the new head and higher compression the engine blew in the mentioned race with just 18,000 miles put on after the head job. Later we found out we should have installed a thicker head gasket to bring the compression ratio down a bit, and a mild cam; that along with a free flowing exhaust and the carb jetted, distributor recurved, and the timing advance with the help of dyno tuner in town, we actually could get the car to run low 14's in the quarter which was way better then stock at mid 16, and would surprised most cars in town. My 62 was entirely original except for the engine work, we did remove the wheel skirts and other assorted items to lighten up the car.