Marine 273 build

69 Cuda 440 said
273 {Automotive Horsepower Numbers}

The 273/180 HP {2-Barrel} with 'low' 9.0-1 Compression is closer to...{165 HP}

The 273 with low compression {9.0-1} and a 4-Barrel Intake and Carter AFB {500 CFM}
is closer to..........{185 HP}

The 273/235 HP 'Commando' with 10.5-1 Compression, and 4-Barrel Intake and
Carter AFB {500 CFM} is closer to........... {215 HP}

Was the "low compression 4bbl" available from the factory? I cant find it listed anywhere- I can only find reference to the 2bbl (8.8:1, 180hp) and 4bbl (10.5:1, 235hp). If so, what was the official rating on the engine? I assume slightly higher than the "typical" 185hp? Or maybe youre talking about a low compression factory 2bbl with a 4bbl intake and carb added? The 20hp difference you state at least makes sense in terms of the difference between the factory automotive 2bbl rating (180hp) and the marine 4bbl (200hp).

Regardless, if the 200hp marine 273 was overstated by Chrysler, then it wouldnt have been any more overstated than the competition. In my experience, the little 273 keeps up with the Interceptor (Ford's marine division/sister from the 60's) 289's and 302's rated at 210hp or so. So, when I say "250-275hp" I guess you could just say Im looking to get 50-75hp more out of a stock 4bbl 273, if that makes sense.:D

The "low compression" 4bbl automotive motor might have been fairly closely related to the marine version... though I believe the marine engine may have had even lower compression (~8.5?) due to the 318 heads. No idea how the cams compare.