In late 40's Oldsmobile created an OHV V8 that was mass produced. They nicknamed it "Rocket". This was a marketing tool to help promote the motor and sale of Oldsmobiles. All subsequent V8 olds motors thru 76 were Rocket motors if they were V8's. There were 11 or 12 different names given to the "Rocket" motors. You can check the internet for Olds Faq and it should provide you with the names of these for the individual years.