What is reason for the H pipe . I want to replace the h pipe muffler section with straight thru pipe. The flow master system is not loud enough for me. What effect can I expect by doing the above.

The H pipe in your exhaust system is designed to equalize the exhaust pressure. Equalizing the exhaust pressure help to evacuate the exhaust quickly creating left back pressure theoretically increasing horsepower. If you use the H pipe the H pipe design is for low end torque, and the X pipe is supposed to help high end rpm. If you want your car to be louder you could eliminate the H pipe or go with a Borla pro XS or a Borla Rx 1 race muffler but that's just my 2 cents.

Loud dose not allways equal FASTER but I like what your thinking ! Do you know what kind of flowmasters you have the 50 series are quiter than the 44s  & they have a smaller race muffler that I cant recall what series they are ther abot 12 inches long.  I purchased some muffler eliminator pipes with the tips welded on. They would have been great if the tips were on correctly I had to cut them off with a band saw and tig them back on so the fit correctly in the notches on the rear bumper.    can I ask what kind of intake, carb and heads you have on the 84 ? I have 2- 85s & I removed the TPI on the Red one to get more fuel & air into my motor  

The flowmaster system uses series 40 as measurements indicate. Strange thing, I can look into the mufler outlet and see the inlet pipe. There should be baffles obstructing the view of the inlet. Folowmaster says the muffler may have cut open and baffles removed. When I record the car idling, there is steady iritating tone that is recorded and heard on play back but not heard by my ear without the recorder.

Since mufflers are straight thru I plan to bypass the resonators with straight pipe should be loud enough

I had flowmaster 40s on a SuperCoupe. I knocked one off on a parking block. It sounded the same so I took the other off and ran with resonator only. I have 50s on the Vette and it still loud but tollorable.

You really shouldn't remove the H pipe.  I have a 95 with the SS Magnaflow cat backs.  They are so loud you need ear plugs when accelerating.   The sound is awesome but very annoying on trips.  If you want some great growls when heading into a car cruise get electronic cut outs.  I am considering them since I may get some Borla or Corsa mufflers so its quiet when on a long trip.  Go over to you tube for cut outs on a SRT Challenger.  Good luck.