caps, thicker, longer connecting rods, and a distinct firing order (1-3-7-2-6-5-4-8 vs. 1-5-4-2-6-3-7-8), adding some 25 lb (11 kg) to the engine's dry weight. The distributor is slightly different to accommodate a larger oil pump shaft and larger oil pump. Some years had threaded dipstick tubes. It had a unique head