Cletus-wake up!
On a stock '54 235 I put a set of Smith-Rieser pressed steel headers (just a sheetmetal version of a 'vette exhaust manifold). This was in 1961-2. I used a stock tail pipe, slightly bent to suit, for the dual side. The header end was 2" dia, the tail pipes were !-7/8"(?). I used the long Smithy steelpaks (under the front seat)L_O_U_D! when in the Raaap mode they could break glass it seemed. Later went to some oval glasspaks (douglas (?). A lot nicer(meaning quieter). After inital installation, I had to change the idle mixture in order to start it (no main jet change was necessary). When backing off it had a pleasant "rack-back" with random popping. The quietness of the mufflers did not affect these characteristics-just the loudness of them. To me stock mufflers were 'way too quiet, for all the hacksaw/welding work, I wanted some noise!
If you are old enough to remember the first of the emissions cars with smog pumps on the stick shift models (1968+), the V8s would really sound bad with loud pipes when you backed off- the super lean stuff (which was a controlled vacuum leak) with retarded timing really messed with the exhaust sound when compared to the '67 models which were still rich and smoggy, but sounded right (the way God intended Chevys to sound).
A crossover pipe will just about wipe out the good split manifold sound - if it is a split manifold with a welded up plate seperating the manifold into two seperate chambers, a small (1/4" dia hole) will cut down on the harshness of its sound, it will tend to sound more like a 6 cyl Porsche's growl. Not bad but not the classic split manifolds sound that we all loved to hear in a tunnel!!!
I think the length of the tail pipe determines the "rackback" and popping on decelleration. Split manifold chevy ll's(mufflers under the BACK seat=short tailpipes) did not rack back with the vigor of the longer piped predessors.
Had a 250 '67 pickup with Hedmens and two flowmasters-wow. It had a snarl due to the collectors with very short (in front of short wheelbase rear tires)tailpipes. Really a slap yo' face sound-almost had an aluminum flywheel abruptness, you could really make the pedestrians jump when you went by them with a little blip of the throttle! Of course, the car alarms in a parking garage were fun too! I was the king of pipes in a tunnel.
Have personally removed glasspaks from a very pleasant '56 265 V-8 and put them on a'52 216 chevy and got tickets the first night out (the old split manifold strikes again).
Its all really trial and error, and these are my results over the years, I hope this kinda sets you in the right direction.
Edski
