273 rocker arms

The 273 I had lasted over 150,000 miles with little maintenance. Adjusted the valves when they got noisy. 2 bbl car with light springs? Decades ago.

273 adjustable rockers require a 273 rocker arm shaft. The holes in the shaft point to the carb base [on both sides]. I believe the banana groove only came from the factory on 340 six pack cars.