Althought my original 1970 Chrysler Corporation Dodge Service Manual for Dart and Challenger models states at page 11-2:
"The dual exhaust system used on models equipped with the 426 Hemin engine, uses an "H"type exhaust pipe arrangement" (...)
Then there are pictures of single exhaust systems, and dual exhaust systems. The Dart 340 had a dual system, no H-pipe. The 225, 318 and 383-2V challenger had a single system. And under the picture of the dual system including an H-pipe it says:
"Challenger 340, 383-4V, 440-4V and 426 Hemi engines".
Not realy unambiguous, but I tend to judge the "Hemi comment" in the text on page 11-2 to be less excluding other posibilities than the "picture comment" is including them. I hope you all understand what I mean. That is as far as I judge this only source. Any other conclusions from printed sources around, other comments?
Off course I am curious what leaving the H-pipe out would make a difference. But as far as sound is concerned: I like very much the sound of my own car. My 383 Hipo dual blows a dual exhaust with H-pipe with Flowmaster Performance Street strip "40 series" and it sounds low. Lots of low frequencies, very little high frequencies. And medium to fairly loud. Of course a 440 with its longer stroke would sound lower with the same exhaust. But my car sounds lower than most 440's with other systems I came across. Myself I would not go without the H pipe. As far as the stereo effects
are concerned, thery are less pronounced but they are still there. And hey, who needs them. And then I myself like any bit of (allmost) free torque. I wish I had chosen an X pipe.
Ciampone, I know you don't have many V8's around, but go check and listen different setups on a meeting.