The Final Product
Once everything was completely welded together, the header was installed back in the mocked-up chassis for final fitment verification. The photos illustrate the final routing of all the tubes and how they fit relative to the engine, chassis, and the other tubes.
I routed the first tube (cylinder one) toward the firewall right out of the flange to provide maximum clearance from the upper A-arm bushing. From there it goes over the steering shaft, behind the motor mount, down and around the oil pan ears (I'm using a C5 Corvette pan), around the bellhousing, and finally to the collector in the upper inner position. This tube makes seven curves along its way. The second tube (cylinder three) takes a similar path over the steering shaft but goes up enough to allow the third tube to pass underneath it. It then takes a fairly short path to the collector in the lower outer position. The second tube goes up like this to create length (having it go up and around the third tube added an additional 4 or 5 inches) so it can get all the way to 36 inches when it reaches the collector. This is a change from the original design (look carefully at the route the second tube was taking as simulated with welding rod and you can see the difference). The second tube makes six curves on its way to the collector. | 
The third tube (cylinder five) heads toward the front of the vehicle, over the steering shaft, underneath the second tube, then back around it, and down to the upper outer position in the collector. The somewhat tortuous path (tube three makes seven curves in four different planes) is to create length. As the exhaust ports get closer to the collector, their corresponding tubes have to work harder and harder to achieve the desired length. |
The fourth tube (cylinder seven) is the simplest--it doesn't have to cross over the steering shaft, and since the other three tubes all go away from the block to clear the steering shaft, there's lots of room left near the block. This allows the fourth tube to take a straight path down and toward the front of the motor where it clears the motor mount, changes direction, swoops around the oil pan ear, and then into the collector lower inner position. It makes four curves in two planes. | |
Summary
This is the first header I've ever made, and I'm happy with the way it turned out. It's a true equal-length header (all the tubes are as close to 36 inches as I can accurately measure) as measured down the centerline of the tubes. The fit is excellent: the collector is only 1⁄4-inch closer to the ground than the pinch welds on the rocker panels, and it's pointed right at the exhaust cutout in the tranny crossmember. There is plenty of room for the steering shaft, oil filter, oil- and water-gauge senders, and suspension. And now for the passenger side.... CC