Americans... tssss
@Kilgon if anyone is running Hookers 6115's with EFI and if they have had any issues because of them
I can tell you right now: you're gonna have issues. As said I have these, tho not the nice look yours have, mine came with the car, had may be 500 miles and yet full of dents because they are too low and po obviously had touched many times. They have this zinc rough protection that you could find in the early days of these but they are looking bad and need a new protection.
My first idea was to do juts that and keep them, because 429 headers are simply idiotic expensive, as if tubbing for a 429 is more expensive than for 302's...
But something else happened since then and now I know I want something else, as I already have the sniper for this engine.
They have 2 flaws aside the obvious "grab anything from the road " design. The first most obvious, being in 3 pieces, 2 will leak for sure, no matter what you will do unless you'd weld, making impossible to remove them without cutting. They will leak simply because at the joins you have twice the metal thickness, the enlarged tube will also expend when hot or during cooling at different speeds causing a gap. You can't really fix this leak. So even if you managed to minimise to the max the leak, you know there will be foreign air entering the system.
and the second, and actually what caused my 73 to be stuck on my driveway for 4 weeks, are the flanges. They used the classic "press tubes in in flanges from behind, weld here and there and call it good" design. On my 73, which had since I started drive some fluctuation in AFR readings ended up after a good run one day into a AFR 35, or in other words, the max reading for lean the sniper O2 sensor can dispatch. It went from a perfectly running car to a car that went straight into flooded condition the next day.
I won't go into the details and the fun to actually find the issue, not mention the new o2 sensor bought or the harness swap, the hours on Holley forum, the attempts to log before engine dies etc...
Let's just say that it was only when i finally got mad enough that I finally found how i could end up with such extreme readings. Even Holley suggested after all tests were done that the ECU might have been defective, after all it was an early gen of the unit.
As said, the whole thing turned me kookoo, and at some point, tired of guessing, I decided after 2 times checking flange/replacing header gasket that I wanted inspect the header in detail out of the car.
Turns out, it was a mix of things: The way these Hedmans are made, exactly same as the Hookers, is the pressing thingy. Just like he hookers, only few welds keep the tube in place. But because these had run many times, went thru the heat fast, cooling down circles. Some space between tube and flange developed. No gasket could fix that, because it was both on the inside and the outside of the tube, but where its squeezed into the flange. There were also 2 holes due to corrosion there, that I guess were enlarged the last day I ran with my lead shoes. All tight enough when hot and bad the next day.
I needed weld the flanges and tube together to have them really air tight. Back on the car, cfg reset, it started right away, and was running with perfect AFR target and no longer tiny fluctuations.
My hookers and likely yours even if much more pretty, are having the same fabrication method. This means soon or later, the metal will expend and not take the position as it would normally do for some reason and tiny air passages will appear. Tiny bits at a time the very same issue I was having will occur on these I'm 100% sure.
So as posted in another thread, I will look for another pair of headers, preferably stainless. Like these and first thing I'll do after welding a bung before install, is air pressure test them and eventually weld any leak right away and be sure this never happens again.
http://www.fordpowertrain.com/fpaindex/Mustang1.htm
if you keep the Hookers (they are not cheap and it would be understandable), I would air pressure test them without the 2 pieces and make sure the flanges are really welded. Then after install, look for some kind of sleeve for the 2 connections.