We got a new toy, but it needed...
We got a new toy, but it needed a full exhaust system install before the fun could begin.
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.
We ordered a set of tti 151/48...
We ordered a set of tti 151/48 to 131/44-inch step headers, and a full 3-inch system to go with them. A real driveway install, we jacked the Duster up at home, set it on tall jackstands, and got to work. Is a real do-it-yourself bolt-in performance exhaust system a reality or just wishful thinking? We were about to find out.
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.
The left-side header on an...
The left-side header on an A-Body is typically a load of work to install with most brands of headers. In the worst case, it can be a grueling full-day job in itself, requiring plenty of clearance mods. We've been there. The tti headers feature this slip tube connection on the #7 pipe, which makes quite a difference in installation ease.
The starter needs to come...
The starter needs to come out to gain clearance for the left-side installation.
Likewise, for a manual-shift...
Likewise, for a manual-shift car like our four-speed Duster, the clutch bellcrank assembly needs to come out for clearance.
The left header slips in from...
The left header slips in from underneath. Only the three forward tubes need to go in first, making all the difference in clearance. Typically, with other header designs, getting in the driver's-side header can be an ordeal. This assembly cleared and went into place with no fuss at all. The common tube layout on the driver's side of most A-Body A-engine headers places the forward three tubes under the draglink, leaving as little as two inches of ground clearance. We've crushed plenty of those over the years in street driving. The tti layout has the tubes above the steering linkage, so speed bumps, driveways, and dips can be negotiated like normal.
Once the forward tubes are...
Once the forward tubes are loosely bolted to the head, the slip tube for cylinder #7 can go in. No clamp is needed here, as the tube tapers in for a tight fit.
A-Body headers we've tried...
A-Body headers we've tried in the past required the starter and headers to go in at the same time, and header removal to replace the starter. It can drive you to slit you're wrists. The tti headers don't capture the starter-even the stock Mopar style. We used a mini-starter from ProForm, which may actually be tougher to angle in. We puzzled over it like a Rubic's cube, and eventually found the trick to angle it in with the header bolted solidly to the head. The ProForm starter cranked our 360 over with ease.
Here's something else you...
Here's something else you almost never get with A-engine headers-the ability to put the box end of a wrench over the header bolt. Ever try getting them tight with the open end and about a 10-degree range of motion? Thankfully, the tti headers provide the clearance so they can actually be bolted up tightly. We also liked the premium quality header gaskets.
Here's the left header from...
Here's the left header from the top. Those familiar with typical A-Body headers will note that the layout doesn't have the usual tube passing over the #5 and #7 sparkplugs, which often requires replacing those two wires, and almost always cooks them after awhile.
We prepped the right side...
We prepped the right side for installation by dropping the steering linkage at the idler arm and removing the stock 90-degree oil filter adapter. We also slipped back the torsion bar since, with a manual car, the bellhousing area becomes quite tight when trying to swing the header in place. Had we had the car raised higher or on a lift, it may not have been necessary. As it was, we opened enough clearance to park a truck beside the engine.