Perhaps it should be a Super-Duper 273 ?

The dual sparkplugs of a 5.7 V8 are such an advantage that engine should be the starting point.

(Since even the late dual sparkplug 4.7 have bad reputations I will not consider those.)

An air to fuel ratio of more than 20, perhaps even 25
can gain a lot,
and you “probably” need fuel injection to keep all 8 cylinders even.

Dodge Ram, or maybe Dodge Magnum station wagon?

Better aero of Magnum would help a lot.