debating exhaust changes for 360

Not looking for stock. 

Not looking for super quiet.

Want to keep performance mufflers - maybe not these, maybe I will.

IF I change mufflers it will be to another high-performance muffler. 

I truly believe that a better system can actually improve not just sound but power as well - better scavenging. These pipes sure don't help that part one bit.

Not looking for anything I would do myself. 

No way would I ever buy a kit and then have to spend the day figuring out how to make it fit and then curse all day trying to bend and weld pipes.
I don't do custom exhaust. 

The engine isn't stock - it's bored, cam, 1200 cfm worth of carb, hooker headers, soon to get roller rockers. There may be other tweaks in the future.

I think the PO went crazy and used New York City municipal water pipes in there. I bet they'd flow 10,000 gallons of water in 15 minutes. Well, perhaps not, but it's for sure overkill. Those huge pipes on this car are crazy.

If it's a bit more loud than my 70 with the sidepipes that's fine. I just want the harsh or shrill out of it, the highs.
I'm looking to keep if not gain power and mellow it out a bit and get the exhaust out the back and not under the car  - not under a 40 year old car, anyway.

I'm looking for ideas for custom and was wondering about using X vs H, etc.

Front section doubt an "X" is easily done and optimized with stock-type routing through the stock transmission crossmember, so if wanting a cross-over an "H" is much simpler to do.  

No cross-over gives a more old-school sound and doubt peak power suffers. 

Muffler selection is likely to make the biggest difference in sound and is tough to select as it's based mostly on personal preference. 

Hence, why asking about exhaust choice on a forum gets a wide range of responses.

Ultimately, choose what suits your taste.  

My clearance issues are with the mufflers hanging down from those huge ten inch pipes (ok, so they aren't ten inch pipes, but they may as well be as that would be as silly as three inch pipes on this car)
The headers clear ok, the collectors so far haven't hit - they can't because the car hangs up on the mufflers first! HAHA

 I mean seriously - the differential was fun to change because it goes OVER the pipes on this car - yes, the mufflers dump into short pipes that sit UNDER the axles. 

Here's the sort of info I was seeking for the most part - although tips on pipe size for a built 360 are helpful, too......

From what I've been seeing, a connection or "cross-over" between two otherwise distinct exhaust systems does tend to help power and sound due to the scavenging and smoothing out of the exhaust pulses. (as I alluded to in another thread related to tuning, wave reflections, etc.)

If there wasn't something to it, there'd not be so many books and articles on it, and folks like Tony and Ken wouldn't be spending the dime to make it happen. 

I also have found in other forum posts here using a search that the 40s do have a more harsh sound than the flowmaster 50s........ and that's also the sort of info I was looking for. that's not personal preference, but a statement that muffler x sounds higher or more harsh than muffler y.

The X cross is just back of the front u-joint. 3" to the mufflers and 2-1/2" from there up and over would be nice and tight. 3" above the axle would be very tight and also not give (to me) acceptable clearance between the gas tank and leaf springs.

The Borla XR-1 muffler seems of interest me.

Also I put SS heat shields attached to the floor between the muffler and floor as I wanted them tight but did not want to set the car a light.

gtoman_us wrote: For what it is worth and referencing my 65 GTO. Last year I elected to not use a cross or Y. The ultimate reason was serviceability. I did not want to have to add the step to drop the exhaust for driveline/clutch R&R. Something to consider. I am lucky with a large Active Pontiac community I got to sound shop my muffler choice and target what worked for me. If you can wait until Auburn or GAD it really helps to hear what you like. I elected Walker Super Turbo on 2 1/2 aluminized pipes

  This was why I had the duals put on my 79 AMX with turn downs. (because I knew I would be removing it). and this is the biggest issue with either the H or X pipes..

it would cost more, but maybe put flat flanges in front of the mufflers so you could romove the X or H pipe to remove the transmission.... Just a consideration.