A GMC person would smirk at your analogies, Deve (as would a mathematician).
All the GMC engines (GMC 228, 248, 270, 302) were full-pressure/high-pressure engines.
I think all had insert rod bearings.
All would be considered full-pressure/high-pressure.
All were supposedly cast with a better/harder alloy/metal-mixture (I think more nickel).
All had superior carburetion, usually Zenith (or, Holley AA-1).
Comparing a 270 to a 235 is interesting.
The only "superior" technology that a contemporary Chevrolet engine had compared to the GMCs was the 58-63 261s had full-flow oil filtration (none of those GMC engines had that technology).
