273 to 318

IF you rebuild the 273, pistons are the hardest thing to come by. Look to Egge for pistons. They cast there own and to your spec for ratio. With this in mind, you may remember the D-dart? A 273 powered Dart for D-class racing that pumped out 275 HP.
I'll just say there are better cams with broader ranges of power these days rather than going back to a similar old tyme DC cam. Any whoooo!

A 318 (rebuilt and pumped up even a little) could be discused as the 273, like said above, and not only would no one know, but it will perform very well. At 45 cubes greater in size..........