The Rocket 303 was one of the first OHV performance engines. Saying that Olds didnt know how to make a performance car is false, many people say the 1950 88 was the FIRST muscle car. Midsize car with V8 power from the full size category. Olds won the very first NASCAR race and repeated that a lot in the 50s.
Olds was given the HURST deal in 67 to appease them for not getting an F car. Thus the 68 H/O was born.
You are correct in saying their marketing sucked. Here is an ad for the 65 442, not something that appealed to the youth market.
There is another ad in 65 that doesnt even show the car, just some kicked up rocks and the tag "442 was here"
The cars were very good, but the marketing was lame.
And just a footnote to all this, once the muscle wars ended the Cutlass became Americas number one selling car. Olds jumped to number 3 in sales.