Slant six dual exhaust proposal

Mostly completed the mechanical stuff on my '63 Dart: rebuilt '74 block 225, block decked 0.40, polished ports/hardened valve seats, Offenhauser intake with Holley 390, Dutra front manifold/cut rear manifold, 10" clutch, A833 trans, 8 1/4 Sure-trac 3.21 axle and all rebuilt front end with '74 disc brakes/dual master.

The current exhaust is just cobbled together with a pair of 2" tubes leading from the exhaust manifolds to individual Thrush glasspacks and 2" outlets exiting in front of the left rear tire; no crossover or h-pipe...all this stuff is off the shelf pre-bent exhaust clamped together. Ridiculously loud, and it just lights up over 3200 rpm...

I'm considing "doing it right" with the exhaust, and here's the suggestion:

Two 1 3/4" head pipes from the Dutra/rear manifolds to a single dual inlet/dual outlet muffler (Jones Full-Boar with the inlets bushed down to 1 3/4") with two 2" tailpipes exiting in front of the left rear tire.

The rationale for the smaller head pipes is that the stock exhaust is a single 1 7/8" or 2" all the way from the manifold to the rear bumper...restrictive for any performance boosts, but I feel that doubling that capacity is overkill and may actually hurt performance by reducing exhaust velocity and scavenging effect. Also, space is at a premium until after the clutch Z-bar, and finally smaller pipes will radiate less heat into the engine compartment.

The dual-in/dual-out muffler should provide some smoothing of the sound and reducing resonance.

Any thoughts?