Chris Jones's '67 MGB V8 Conversion

One of the problems all converters will have is the choice of which way to get the exhaust from the heads to back of the car. When I started my project the most common method was the use of the block-hugger header. They had a bad rap because of a propensity to crack as well as the reputation for poor performance. I wanted to tackle the header problem at the outset of the conversion; to build the best set of performance headers I could, and work around the headers in the placement of steering and other exhaust components. Dual exhaust was a requirement for performance and aesthetic reasons.

I started by learning as much about header design as I could and found my way to Headers by Ed. Ed had been building performance headers in his shop for years and a long conversation with Ed led to a 4 into 1 design, with 1-1/2" X 38" long primaries that would give me the maximum power in the RPM ranges that I wanted for a strong road machine. I ordered all the J-bends, U-bends, straight pipe and preformed collectors from Ed.

I wanted the exhaust to fit inside the car and was reluctant to cut the inner wings. This requirement forced me to come up with some method to snake all this pipe down and around the starter and steering. I first maximized the space available by making motor mounts that left as much space as I could get between the starter and the oil pump and moved the chassis mounts as far forward as needed. I then found some flexible plastic conduit (a corrugated product used to run communication cable) that I cut to 38" lengths. I fabbed up a temporary sheet metal exhaust flange to hold the plastic tubing to the head's exhaust ports and began to bend the plastic to the shape needed to worm down through the available space. To get the plastic tube to come together at the same point (representing the point that the tubes would join the the collector), it became apparent that I would need to loop some of the tube outward below the chassis "frame" below the inner wing. Then it also became apparent that I would need to have a break-joint to allow the headers to be removed while installing the engine. (In practice, I am able remove the bottom portion and leave the upper portion attached to the heads while installing or pulling the engine). I set the flex conduit in position using a heat gun and removed it to begin to fab the header in steel, copying my bends in steel tube. I made exhaust flanges from a sheet of 5/16" mild steel, and started on the tubes. After many hours of cutting and fitting and tack welding, then repeating on the next tube I had one side completed. The tubes were then removed from the exhaust flange and TIG welded to completion. The assembled tubes were then brazed to the flanges and welded to the collector. After having a shop grind the flanges flat, They were sent to Jet Hot Coatings to be ceramic coated. They were mounted to the heads with .060 thick asbestos-paper hand-cut gaskets.

Although it took several more years to test the fruits of my labor, I'm very happy with results and know that I have a set of very unique headers!