This is a mock-up shot for...
This is a mock-up shot for the lead. All safety procedures were followed for this story.
Aset of well-designed steel long-tube headers will increase power in most any early or late-model Pontiac. Depending on the brand and design, they can run from mild to wild with regard to price, fitment, and performance.
After making a substantial investment of cash and labor, the worst that can happen is denting those low-hanging long-tubes on a road obstruction with your street car or landing hard on them after a wheelstand in your race car. A crushed header tube will reduce performance because of diminished exhaust flow, so it needs to be repaired or replaced. If you are running a set of $79.95 speed shop specials, you may be better off just replacing it. However, as many of us already know, to get a set of headers that perform and fit well in a Pontiac engine compartment, you have to pay a premium for them, so a low-buck repair is probably a more cost-effective choice.
Header repair seems to be a lost-art nowadays, but back in the day, a method was developed using a combination of heat and compressed air to expand the header tube back to its original form. This type of repair is typically done with the header or headers removed from the car due to safety considerations.
The key to using the repair procedure is to ensure a leak-free seal on the primary and collector sides, so when the damaged header is heated sufficiently, the air pressure can be regulated to push the dent out.
Steve DuSold of DuSold Enterprises has been performing repairs like this for many years. Follow along as we show you how to repair a set of vintage A-body 13/4-inch primary long-tube headers with 3-inch collectors. The driver's side header took a major hit and the passenger side a minor one. We'll begin with the easier fix and then move on to the more difficult one.
Time Saving And/Or Low Buck Tips
On the first attempt to create a header block-off plate from 6-gauge steel, it flexed just enough to allow minute leaks, so stick with 3-gauge if you use steel instead of plywood.
To find a slow leak, spray glass cleaner around each port to look for small air bubbles, or fill a 55-gallon trashcan with water, dunk the assembly, and look for air bubbles.
If you happen to have a thin 9/16-inch wrench, it makes it much easier to get to the nuts on the center port.
The vinyl gasket sealed easier than the header gasket and is very cheap and durable.
The passenger side header...
The passenger side header was inspected by Steve DuSold for damage, and a small but noticeable dent was identified on a primary tube. This will be the easy fix.
Heavy damage was found on...
Heavy damage was found on the driver's side, as almost half of the primary tube has been collapsed. There are deep depressions in the crushed area with creases in the metal. Using this header on your Pontiac would kill performance. Since this is close to a worst case scenario, it will really put the repair procedure to the test.
To repair the headers, a piece...
To repair the headers, a piece of 5/8-inch thick plywood will be used. From Home Depot, a Roppe Corporation Pinnacle vinyl wall base (P/N 662756370754, retail $1.86) that's 48-inch. long by 4-inch wide and 1/8-inch thick, and a 3/8-inch Irwin Speedbor woodworking bit (PN 0247121200440, retail $3.18) will also be employed.
An air-pressure gauge at the collector is optional if you have a regulator and gauge on the compressor. As long as the line doesn't leak and the air hose isn't so long that the pressure at the collector is markedly different (the longer the air-hose the more the pressure drop), the gauge will be relatively accurate.
If a set of headers is prone to being damaged in the same spot, add a metal "skid-plate" over the susceptible area.
One of the cheapest ways to have leak-free headers that won't blow-out the gaskets is to coat both sides of the gaskets with RTV and let them dry before installation. The RTV provides a cushion that will allow even slightly deformed flanges to seal.
If you have can weld, look closely at the collector bolts we used. Rather than having to struggle to get a wrench on them, a short piece of welding rod was welded to the side of each one. Whether the bolt is being tightened or loosened, the tab abuts against the pipe, making it very easy to remove or install the collector nut. Total price on this is under $1, as welding rod and/or spare nails lying around the garage can be used to make the custom collector nut.
A well used Mr. Gasket exhaust...
A well used Mr. Gasket exhaust header gasket for D-port heads was placed on the plywood. In order to adequately cover the gasket and provide some surface area to clamp down on, it was determined that a height of 31/2 to 4 inches and a length of 23 inches would be required. A Sharpie marked the measurement and the six exhaust bolt-holes were traced, as was the entire gasket for illustration purposes.
The plywood was cut with a...
The plywood was cut with a circular saw.
It was then clamped down in...
It was then clamped down in a vice and the 3/8-inch holes were drilled far enough through the plywood just to see the point of the bit coming out. Then the drilling was finished from the other side, so as not to rip the bottom layer of plywood off.