Bigger is not always better - sometimes it's just more
Big 2" primaries like a 500 cube V8 could take would lose considerable power under the curve. Big 2.25" intakes just won't fit right on a small 4" bore and would be silly at stock rpm limits.... can you say "pig" - that's what you'd have.
Mopar, I believe you misunderstood the above quote. What he is saying is that what works on a 500 ci big block may not work on the Viper as it really is essentially a 10 cylinder small block, albeit a big small block. The Vipers smaller cylinder diameter will not support the same size valves as a big block and the per cylinder flow is less, thus smaller primaries end up working better. It really isn't a cubic inch question, but how many cubic inches per cylinder. The Viper has 48.8 (Gen I & II) where a 427 has 53.4, a 454 has 56.8 and a 500 ci has 62.5. Thus in a per cylinder comparison the Viper is lower than the big blocks and on the high end of the small block scale.