Here are some of my observations, from my earlier years and up until now, decades later. No more, no less.
few of them actgually "fell into place" without some dings top the pipes for chassis clearance, ty
We don't know how the poster came to own the Imperial, but usually, getting it to run better is a normal situation and one which can result in discussions with "advisers"/other people who might tend to influence the poster. BTAIM
Upon their inspection of the car, they determine that "headers: might be a viable option as "headers are available for any vehicle on the road", or so they might suspect. No immediate thought of cost of the headers or related items (a full dual exahaust system). Or the possibility that that same amount of money might be spent elsewhere on the car for possibly better results. Headers have always been a somewhat popular upgrade, especially in the GM and Ford arenas, so they, in their mind, might be good to do on the Imperial.
Back when there are a zillion brands of headers, many sets could be had for about $200.00 for the best ones, Thick-walled with thick flanges and good gaskets. BUT few of them actually "fell into place" without some dings/clearancing actions, typically. Even some "war stories"! Still, a popular upgrade for many, but the B/RB HP manofolds were designed to be almost as good but without the many long-term issues which tube headers tended to have, back then. Serious racers still gravitated toward headers, though.
Perhaps, the poster might be aimed more toward TTI for any exhaust inquiries? So that a comprehensive exhaust system might be estimated? A vendor that tends to be more intimately aware of Chrysler issues than other vendors might? I'm not sure (after looking on their website) who or where Southwest Speed might be, but it appears they are not Mopar-specific, not a bad thing per se, just an observation. Which generated the reply the poster received from them on his "Imperial" inquiry.
To me, headers are not usually the first upgrade which might be made, but one which could come later (due to their explosive pricing over the past years). In getting ready for that later possibility, a good undercar 2.5" OEM-style dual exhaust with '72 Imperial mufflers (allegedly the same restriction as the Street Hemi OEM muffler, but in a C-body size) would be a good place to start. Which is where TTI could come into play!
Next thing would be to determine if the Chrysler HP manifolds would actually fit, considering some of the differences in underhood placement on those Imperials, when compared to a normal C-body 440HP installation. Then finding a good set at a decent price, so TTI could build the lead pipes to match the manifolds for a more-OEM-level fit and durability situation.
Certainly, a full TTI header/dual exhaust would be a conversation piece at any cruise evemt, especially if the headers are wrapped in ThermoTech-type head shield wrap. BUT in order to get that "right", it could well require the motor to be pulled out, the headers installed, and then the motor dropped back into place, "clearancing" as necessary, as it is dropped back in. NOT nearly the same as with a '69 Camaro small block!
Some thoughts and observations,
CBODY67
