Straight Pipes

I'm getting ready to put a Jegs 2 1/2 inch exhaust system
on my 70 Dart Swinger.
I will be adding a same size H pipe in the system,
my questions are:
Where in the system is optimal for the H pipe after the headers,
and I may not run mufflers, but the system will exit the
rear, how loud would it be.

The 360 motors pretty stout with high comp and 509 cam.