Doug's cannot know what the scenario their product is going into 100% of the time....so sometime there could be issues. They design it to the stock setup and probably have a little leeway built in.
I don't fully agree with that statement.
I have spent time in both design and manufacturing in the auto business. It is the company and their engineer's responsibility to make sure that their product fits in all cases. This means that they should seek out the worst case scenario and fit to that.
My first time in manufacturing plant, the company made a "slight" change to the bolt that held the rear bumper on. When the change hit the plant, we found out that the "flag" on the bolt that was used to prevent rotation in assembly so only one tool was needed to tighten the nut, would sometimes rotate and cut one of the wires on the trailer harness for factory trailer tow trucks.
We had to jump through hoops to correct this, so as not to send out trucks with a short in the trailer wiring. When we identified the solution to the problem, we had to test build it on ALL VARIATIONS THAT COULD BE BUILT. This meant that I had to verify that it would not create a problem on all frames with and without trailer tow. Luckily the plant I worked at only built half of the possible variations, but I had to make sure that I tested it on ALL 12 OF THE FRAMES THAT WE BUILT! (There were 24 different frames for all variations of the truck). Someone in the other plant that built the other 12 frame variations had to do the same at his plant. Not all 12 frames are used evenly. Some frames are used more often than others. I had to hunt down and find all 12 frames that were being built and wait at the bumper station to verify that the new bolt flag did not catch the wires. In some cases we had to wait an hour or two for the rarer frames to get to that station to verify them.
Luckily our new fix worked and we pushed the change through as fast as we could. After that "hiccup", they made it mandatory that EVERY CHANGE HAD TO BE TEST BUILT BY AN ENGINEER IN MY GROUP BEFORE ALLOWING IT TO BE RELEASED. Even a "simple nut and bolt change"...
When Doug's or any header company designs a header, they should seek out one car of each variation to test fit it on that they plan on releasing it for. In this case they should have used a 67 - 72 power steering and manual steering car and a 73 -76 power and manual steering car to test fit and verify that the parts fit correctly - MINIMUM. The price of the cars gets to be written off on their taxes as part of the research and development cost for developing new products. It's a cost of doing business.
What bothered me on the one post where he spoke to Dougs and they ADMITTED THAT THE PARTS MAY NOT BE MADE CORRECTLY, but took the easy way out and said that since he dinged/smashed them to fit, they would not warranty/return them. The manufacturer should be able to identify a bad part and prevent it from getting shipped to a customer. At the end of the manufacturing line in the plant where these headers are made should have a fixture where they clamp the header into a stand, and then check certain critical points on the tubes where the clearance is critical. This would verify that all of the tubes are properly located and fit before shipping the part to the customer. If they do not have a fixture that does this, they are not a responsible or good manufacturer to do business with. I have dealt with similiar parts in my time in the automotive business. It was part of my job to go the the manufacturers of my parts and inspect/question/challenge/ and approve fixtures like these before they were allowed to ship parts to us. It is part of their certification. If the company could not prove to me that these fixtures were capable of identifying parts out of spec, I wouldn't sign off on their certification and they could not ship parts until it was corrected. Part of the certification was to run a known good and known bad part through the fit fixture and make sure that the fixture could approve a part in spec, and reject a part just out of spec. If the header/tubing manufacturer does not have a fixture that does this, his process is not set up properly. A properly set up line will be able to catch bad parts before they can be shipped out to the customer.
That is why it is much harder to be an OEM supplier than an aftermarket supplier.
And good for Summit for replacing the headers for him. That is a good company to support and do business with.