What would it take to make 1.44 lbs-ft per cid ?

Interesting topic. I think it's more interesting than hp/cut in because you can always head flow and rpm your way to higher power.

I don't have a ton to add here. I would ask, what fundamentally yields more torque? Do that.

I would also ask, what fundamentally reduces parasitic losses. Do that.

It may be that there's a sweet spot where you get better efficiency between bore stroke and displacement. Put another way, I'd bet that st the extremes you get reduced tq/cu in. So a 273 or a 572 might make lower tq/cu in.

Stating the obvious here, but a cam and intake matched to both make peak torque at the same rpm seems like a big fundamental one to get right.