Offenhauser Dual-Port 360* Intake ~ 'Was It A Gimmick'

For what it's worth, I used to have a pair of them. I ran one on my 383 in my Roadrunner back in the 70s and I put one on my 318 in my crew cab dually.

I was pretty young and dumb at the time I chose one for the Roadrunner. I was just looking for a used aluminum intake to run. Not knowing much about part selection during those pre-internet times, I'd expected to see an ET drop. It didn't make me run any quicker than my stock intake had, but I didn't seem to lose any performance either. One thing that I did notice was a gain in fuel economy though.

Years later when I was putting the dually together I chose many of the same components that I'd run on the 383 even though I had a 318 in it. Once again, I definitely had a noticeable gain in fuel economy as opposed to my stock intake. It may sound hard to believe (and it was a long time ago) but my recollection was that I'd picked up about 2 mpg. The dually was a tow vehicle so there were no track times to compare but performance did improve.