@panteradoug posted:ALL v-8s should have a balance tube.
For one thing, the camshaft timing is designed to take advantage of exhaust scavenging. You can't get that unless both sides are tied together, i.e., balance tube.
Separating the exhausts one side from the other is going to make the idle rougher.
You can hear the rough idle, even on a mild cam, on cars like Cobras and Corvettes with side pipes.
You are giving away torque with that setup. How much? You would need to do an extensive dyno test to find out. I'd take a guess and say in the 30 to 40 lb-ft vicinity.
I am going to agree with you on the crossover pipe picking up torque. I don't have any chassis dyno numbers for my car before and after the crossover tube installation, but the seat of my pants told me that there was more available power after the installation. The only problem with installing a crossover tube on a Pantera's exhaust system is that there is only one place to install it and that does cause more heat to be pulled into the air conditioning condenser. Of course, as soon as you move the condenser to the front of the radiator, that exhaust crossover heat problem goes away.