Large valved 273

What’s the power goal.
Every 50 hp can make a big difference expense to the build.

Plus rpm goes up quit a bit.
These are just guesstimates.
Probably on the minimum side
250 hp 1500-5500 rpm
300 hp 2000-6000 rpm
350 hp 2500-6500 rpm
400 hp 3000-7000 rpm etc..

300 and under is the dividing line can get away with mostly stock parts just cam 4bbl and headers and some mill work to get a decent cr. Above that starts to get more involved especially in head and cr.