64 barracuda 273

Excellent choice.

Think about it.
I am a streeter and I'd venture to say that in terms of time spent at low rpm is 90/95% of my driving is below 3000. I have a 4-speed and 3.55s.. Normally, I shift at 2800, for three reasons;
1) cuz my 367 has a preponderance of low-rpm torque on account of the very high cylinder pressure, and
2) it just sounds so doggone good pulling from 2K>3K, and
3) cuz it hits 65=2880 , and then I drop it into overdrive.
You talking part or full throttle shifts?
Guys will say Horsepower is just a number, a fallout of an equation. While that is true, it's still nonsense. Torque and horsepower are intimately married; as long as the car is moving, you can't have one without the other.
100%
The more cubes your engine has, the more torque it will inherently make, and
the more cylinder pressure it makes, also the more torque it will make, and
To a degree, stroke makes torque.
So in the case of the Mopar SBM, what can be better, than a very high pressure 360? Of the SBMs it has the most cubes, and the longest stroke, and high pressure is just a piston swap away.