is this true some guy i work with told me this and i was wondering if he was telling the truth or blowing hot air in my face

 

390 what? Cubic inches? Horsepower?

Olds never made a 390 cu in engine. The closest was the 394 early V8 built through 1964. That motor is completely different from the later Olds small and big block motors and would require custom fabrication to install in a Cutlass. This was never done from the factory.

If you're talking horsepower, the 455 in the 68 Hurst/Olds WAS rated at 390 HP.

 

This is also like the ever elusive "442" cubic inch motor, that non car guys seem to think exsists too...

John