273 commano on the dyno wooooow

LOL, 3.31" isn't in the "long stroke" category, and it's still an over-square engine. Try to get sympathy from a slanty racer 3.5" hole & 4.125"swing !!! SB Mopars have a
nearly ideal placement of valves in the chamber/bore for an inline-valve arrangement. True small bores can restrict flow, but are more resistant to detonation, so You take
advantage of every little gift each particular build offers to the max. It is also not 100% true that heads that flow enough to make 400hp, will do so no matter what the
displacement, there are frictional losses that go up exponentially with RPM, as well as the inertial loads/losses Energy=Mass x Velocity sq. it's not a free ride to 10K just
'cause the heads say they can take You there!! In this sense, You're correct. To obtain that output at the needed R's, a reduction in stroke would be needed to offset the
new demands of such an increase in inertia, and help slow the intake velocity for a given RPM as well.

Lol, I’m not looking for sympathy. The reason I mention stroke is that 3.31 is the same as the 340. Granted it’s not much but if you spin it 9k you’ll need a light rod/piston package. The reason I mention the small bore is that a 2.02 valve won’t fit. It hits the block. And if you want the big flow to make max power for the displacement you’ll need that 2.02 valve. I raced a 273 for a few years so I have some background on this particular motor.