I should have included the two barrel L.A. 273 compared to the two barrel Poly motor made more power per C.I. and got better mileage than any of the Poly motors made.
I've owned and driven cars with both motors, the L.A. motors are way better than any of the those early Poly motors that Mopar stop making in 1966
As far as the size of those Poly motors compared to the L.A. motors how can they be bigger if they both can use the same timing sets as well as those timing sets fitting on the 1957 and 1958 392 Hemi motors?
I'm almost positive that the 1962 and later 318 Poly motors and 318 L.A. motors have the same blocks and crankshafts
BTW, the Poly motors where NOT L.A. motors