When we recently had the opportunity to purchase the well-known Car Craft project Duster from former CC editor David Freiburger (now editor of Hot Rod) we jumped at the chance. Problem was, the entire exhaust system had been heaved into the dumpster behind the HR shop months before. Freiburger had wanted to upgrade the low-hanging cheapo headers and cobbled pipes for a new system, and now it was our job.
We knew what we were after. Starting up front, we wanted full-size, four-into-one headers. Having experienced the typical under-the-draglink A-Body headers with the accompanying nightmare of constant pavement rash, we wanted headers that fit and tucked up nice and tight to the floorpan. From there, we wanted a free-flowing 3-inch system large enough to handle whatever power level we'd eventually have in the car. We knew that 3-inch pipes tend to be loud-a fact of the physics of gas flow though a large pipe cross-section. Even so, we wanted mufflers that controlled the mayhem.
The header decision was easy. We used tti small-block headers in our '69 Dart, and they were everything we expected them to be. The tubes fit above the suspension and steering, and are designed so the starter motor isn't captured by them. TTI offers a stepped header for A-engined A-Bodies, with 1 5/8-inch tubes starting at the flange and growing to 1 3/4-inch a few inches downstream. This is a step up in performance over the usual 1 5/8-inch tubes found in most street headers for this application. The 1 5/8-inch tubes at the flange are a good match for the exhaust port size, allowing for ample clearance to the header bolts, which is always a problem with the tight bolt-pattern spread of the standard small-block exhaust flange. About seven inches down from the head flange, after the tubes turn down past the tightest confines of the engine bay, the tube size grows to 1 3/4 inches-a size capable of handling the exhaust requirements of a wicked street small-block up to the 500hp range. The tti units are made of heavier-than-standard 16-gauge tube, coupled with extra-heavy 3/8-inch thick flanges at both ends for quieter operation and leak-free connections.