Testing the 273 on the dyno....

Comparing my 200 horsepower 277 poly "power pak" of 1956 with the 235 horsepower 273 "power pak" of the mid-60's, I'll note that the 277's compression ratio is only 8:1, and the cam only has .380 lift. Raise the 277's CR to 10.5 to one and give it a .415/.425 lift cam, and I think it would easily make another 35 hp.