[Oldsguy]

Rocket is a nickname for almost any modern OHV V8 engine Oldsmobile made since 1949. Sometimes the marketing was obvious, sometimes not. Your engine is a Rocket whether it is a 455, a 350. If you are sure about the year then it is either a 350 or 455. The esiest way for me is to look at the head on the driver's side. On the lower left corner, sort of below the alternator and above the power steering you will see a Capital letter cast into the head. You may have to clean it with a rag or some spray carb cleaner or engine cleaner to remove the grease and oil if the engine is dirty. If it is a capital letter then it is a 455, look for a C, D, or maybe F. If it is a number or a number with a letter suffix then it is a 350. Look for a 6, 6A, 6a, or 7 (I think). Other ways, the big block is 13 inches wide at the front water crossover on the intake, a small block is 11 inches. Finally, the sure fire way to know all about the engine is the engine code cast into the block below the water neck, above the water pump on the horizontal surface of the block where the oil pressure sender is. Record that number and someone here can decode it for you.