What's the deal with the Poly 318

About 25 years ago I had a ’66 Coronet 500 with a mildly built 361 and my son had a ’66 Satellite with 318 Poly that was almost identically built. Their weight was identical within a few pounds. His was bored .030, and mine .040, both with stock compression, stock heads, Edelbrock 4bbl on stock intake, mild RV cam, dual exhausts through stock mufflers, and MP electronic ignition. Both were automatics with 3.23 open gears, and tires were the same size and brand. My TF had a shift kit, his did not.

At the track, his Poly was a full second faster than my big block every time. On the street, he got five more miles per gallon in similar driving. I don’t know what each engine’s potential might have been, but in normal driving and light track the Poly was a far better engine.

FWIW, I chose a mild ’66 Poly to power my ’56 Plymouth currently under construction.