273 or NOT 273?

The only problem with the 273 is the small bore size.
To make good power you need a 340 bore to make the heads flow properly.
The factory made a good performance engine in the 273 commando, but things have moved on.
Forged crank, fully floating pistons, adjustable valve gear.
Nice closed chamber heads that flow nice with 318 or 360 valves.