If I was to build a 273 would use 4.10 as a minimum, smaller engine need more gear,
running 3.55 behind a 273 is like running 2.76 behind a 360, 3.55 is a compromised gearing for a 360 a 273 would need 4.56 to have similar torque to the ground as a similar powered 360.
Why one of my signature tagline is "If your willing to gear it build it if not build a larger displacement, Or take solace in your compromises."