We're taking a hard look at our High School Hauler project and trying to determine the best course of action for each area we want to upgrade and in what order. Of course, there are no hard and fast rules as to order, but some things do make more sense than others when you look at the big picture. Still, you can really start pulling your hair out when you start to consider, "Do I buy new headers or do I get those cylinder heads I want first?" Yes, indeed, tough questions are an aspect of every build, be it a drag car, road race car, or just a fun street ride.
For the High School Hauler, we knew we'd be getting into the engine sooner or later with some sort of heads/cam/intake package, an upgrade to the 8-inch diff with some gears, and other performance upgrades, so we wanted an exhaust system that would handle these upcoming near-future performance mods and complement our final power level. We decided to upgrade the exhaust first due to the state of the current system, which was as basic as it could be; long-tube headers with straight pipes, a pair of welded mufflers, and turndowns.
While the system was throaty at idle, it was unbearable at speed. What sounded cool 10 years ago when the coupe was a daily driven high-school ride just wouldn't cut it now. We wanted long-tube headers for their tuned primary equal length tubes that promote low-end torque, but we had to make sure such a header would fit around our recently upgraded AOD four-speed overdrive trans. JBA headers had just what we needed in its catalog. The rest of the system is from Pypes Exhaust, where we used one of its mandrel-bent, high-flow stainless steel systems. You can check out a video at the end of this article to hear our finished system for yourself.
At our last track outing, we raised a few eyebrows with the track officials when they saw what our '70 was riding on. While there was tread left on the tires, they certainly were way past their window of usability with dry rot cracking starting to show on the sidewalls. If we were to chassis dyno the '70 and take it to the track for more testing, we would need some new shoes. A call to the Tire Rack for some new BFG rubber wrapped around a set of polished Torque Thrust IIs filled the bill.
The Tire Rack, known for years as the place to go for replacement tires for your daily driver, has continually worked on expanding its offerings. From performance wheels to race tires, and even hard part upgrades like suspension and brakes, the Tire Rack has plenty to offer for every car in your driveway and its classic Ford fitments continue to grow all the time, so if you don't see it on the website, just give Tire Rack a call. It'll get you fitted with the wheels and/or tires you want.
1 After soaking the collector...
1 After soaking the collector hardware in penetrating oil we pulled the hardware from the header tubes, but left one bolt and nut loosely in place on each side to hold the loose exhaust tubes up.
2a The muffler hangers were...
2a The muffler hangers were haphazardly welded directly to the car’s floorpan, even though there were several mounting screw holes already in existence in the vicinity.
2b A few minutes with the...
2b A few minutes with the edge of a cutoff wheel and we were able to separate the bracket without much damage to the floor.
3 Once our utilitarian exhaust...
3 Once our utilitarian exhaust was extricated, it was even more painfully obvious that the shop that made the “system” up all those years ago did the most basic of work. Goodbye turndowns!
4 Moving on to the removal...
4 Moving on to the removal of the old headers, it’s in your best interest (even with stock manifolds) to remove the plug wires and spark plugs before taking your first header/manifold bolt out. Mark the plug wires if you need to, but getting them out of the way will help in removal and installation of the new headers.
5 While we had the use of...
5 While we had the use of the four-post lift from our Dynojet dyno, getting your typical long-tube headers out (or in for that matter) requires heading below the car. You’ll want to ensure your car is raised as high as you safely can manage (borrow “big boy” jackstands from a pal if you need to) to get the headers out. Here, the old headers are loose and resting on the bellhousing ready for us to snake them out.
6 Removing/installing the...
6 Removing/installing the headers can be an exercise in frustration. While the ’70 is a small-block car and didn’t offer us much trouble, some cars will require removal of steering linkages, the starter, or even jacking the engine up itself for clearance. Just be prepared, and for giggles, try the headers from the top, as you never know when you might get lucky!
7 We're using JBA's '65-'73...
7 We're using JBA's '65-'73 small-block Mustang headers designed for AOD transmission conversions like our '70 has. The headers (PN 6610S) feature 3/8-inch thick laser cut flanges, JBA's patented Firecone merge collector, mandrel bent 1-3/4-inch stainless steel primaries, and oversized ports. They'll run you $1,165, but they're a work of art and they fit, compared to what we removed.
8 When starting your header...
8 When starting your header bolts, be sure to turn all bolts in a few threads before tightening a single bolt. This is especially important on the bolts that go on the short side of the primary tube’s radius, as these bolts require the header flange to be pulled away from the head to even start the bolt.
9 We’re going to share a...
9 We’re going to share a little header installation tip with you here. If your header bolts don’t have an internal hex for an Allen wrench to snug them up and your wrench simply won’t grab a flat on the bolt head, turn the wrench parallel to the head of the fastener and use a small wrench to grasp and turn the wrench as shown. This will often get the bolt turned far enough to grab one of the bolt head’s flats for further tightening.
10 Here is why you pay good...
10 Here is why you pay good money for a long tube header. Not only did they drop right into place and offer up plenty of clearance around the bellhousing, but the collector locations are tweaked to work with the downward-facing AOD shift linkage (which rubbed right into our old headers). Just look at all the room between the header and trans linkage.
11 For the rest of our exhaust,...
11 For the rest of our exhaust, we called upon the guys at Pypes Exhaust for their 409 stainless steel 2½-inch dual exhaust kits for ’65-’73 Mustangs. The SFM03S kit includes an X-style mid-pipe kit, extensions, tailpipes, and Pypes’ Street-Pro mufflers. For our ’70 coupe, we chose the quieter, yet great flowing, Street-Pro mufflers, but Pypes has several muffler choices you can choose from and listen to on its site. The SFM03S set us back $495.50.