390 tube headers on a 351C? Maximum confusion

Sunday, time to ask a few questions again so I can move on next week!

When I took over the 73 Mach 1, it was not in good condition. Among other things, the exhaust was completely rusted.

I dismantled it and bought a new one. 2.5 inches should be the standard, as far as I know.

On the first attempt to install it, we encountered the problem that the previous owner apparently installed different manifolds/tube headers.

Unlike the standard manifolds on the 351C, these not only go up to halfway up the engine block but also swing down quite a way and then run parallel to the floor of the interior towards the rear.

This meant that I could not use the H-pipe that I wanted to install.

I would now rather not have to buy a whole new exhaust.

Is there an intermediate piece, even without an H-pipe, that fits as standard?

I seem to remember that the manifolds/tube headers on the 390 and 427 were different.

Enclosed are a few pictures for a better understanding!

Appreciate your help,
Ben

PS: If it's easier to buy a whole new exhaust system could also be a solution.

Ben,
What I can identify on these pictures are long tube headers. There will be no way to install a factory h-pipe. I also do not believe, that a 390 exhaust manifold will ever match to a 351 Cleveland head. If the long tube headers do not touch any parts in the engine bay or below the floor, use them and construct your own custom build exhaust system.
Cheers Frank

Check out the headers and system on @tpj71mach car. https://7173mustangs.com/threads/’71-mach-1-resto-project.40246/

If you want to use those headers, I would just take the car to an exhaust shop and have them custom bend a section for that area. Around my place that would be $100-150. They may even be able to squeeze an x pipe into that section.

Thanks guys, check the surroundings, unfortunately it's very expensive in Germany.

torbsim said:

Thanks guys, check the surroundings, unfortunately it's very expensive in Germany.

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That's the problem. You're measuring in inches but Germany is on the metric system.

But on a serious side. Yeah, with those headers you will need to get some custom work done to match up to your exhaust. IF exhaust work is expensive in Germany then you need to ask yourself "Are long tube headers right for my build/engine/plans". Long tubes are generally better at high RPM. If your plans are to drive the car around and enjoy it as a daily driver and your are not planning on running it at high RPM's a lot, then you might find the answer is to get some short headers (which will still require some exhaust shop work) or a set of stock manifolds. If your engine is a 2V then finding stock manifolds probably won't be too difficult.

But you also want to get that bad boy running. I get it. There is flexible tubing you can use to connect what you have until you get a more permanent solution. You can probably mock this up yourself. You'll need to find a piece that matches up tot he header and also some additional clamps. Is it a good choice long term? No. Will it leak? Probably at some point. Will it look good? Not even close. Will I be able to start it up and drive it without driving the neighbors crazy or doing any damage to the engine? Yes!

Seems like so much work, if even possiibble, to ttry to mate 390 headerrs to a Cleveland , pipe diameters and tuning lengths should also be different. On anotherr note, I remember the four-bolt collector flanged headers as being made by Appliance Headers.

will e said:

That's the problem. You're measuring in inches but Germany is on the metric system.

But on a serious side. Yeah, with those headers you will need to get some custom work done to match up to your exhaust. IF exhaust work is expensive in Germany then you need to ask yourself "Are long tube headers right for my build/engine/plans". Long tubes are generally better at high RPM. If your plans are to drive the car around and enjoy it as a daily driver and your are not planning on running it at high RPM's a lot, then you might find the answer is to get some short headers (which will still require some exhaust shop work) or a set of stock manifolds. If your engine is a 2V then finding stock manifolds probably won't be too difficult.

But you also want to get that bad boy running. I get it. There is flexible tubing you can use to connect what you have until you get a more permanent solution. You can probably mock this up yourself. You'll need to find a piece that matches up tot he header and also some additional clamps. Is it a good choice long term? No. Will it leak? Probably at some point. Will it look good? Not even close. Will I be able to start it up and drive it without driving the neighbors crazy or doing any damage to the engine? Yes!

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And of course we have the German TÜV, which means that nobody in Germany can just drive around in their car. All owners must have a valid certificate and renew it every two f******* years!

Spike Morelli said:

Seems like so much work, if even possiibble, to ttry to mate 390 headerrs to a Cleveland , pipe diameters and tuning lengths should also be different. On anotherr note, I remember the four-bolt collector flanged headers as being made by Appliance Headers.

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Very interesting fact. I was wondering why I have four-bolt collector flanged headers!

I cannot help you with the four-bolt flange, but I made good experience wit M&F Garage in Germany as a suplier of different pipes and mufflers. I made my exhaust system by my own. It's 2,5 inch size with a single muffler in each pipe and a so-called dB-killer at the end. This results in a slight grumble when cruising but a clear pronounciation when you put the pedal to the metal. This also means that you won't stand out during the vehicle inspection. Very important: Don't tell the inspector too many details. This will only arouse his curiosity.

Vicus said:

I cannot help you with the four-bolt flange, but I made good experience wit M&F Garage in Germany as a suplier of different pipes and mufflers. I made my exhaust system by my own. It's 2,5 inch size with a single muffler in each pipe and a so-called dB-killer at the end. This results in a slight grumble when cruising but a clear pronounciation when you put the pedal to the metal. This also means that you won't stand out during the vehicle inspection. Very important: Don't tell the inspector too many details. This will only arouse his curiosity.

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Thanks appreciate your tip! Will looking for them online.

here we go: https://www.mnf.de/Shop/index.php?cPath=1334_1_1243&<osCsid>

and that's an example of the db-killer (db-eater) I used.
https://www.amazon.de/dB-Killer-Universal-dB-Eater-Krümmer-Auspuff/dp/B078K8FRP4

Nice! Thanks

Those are nice vintage Appliance Company headers (as @Spike Morelli mentioned). They came factory painted White in addition to having the 4 bolt collectors.One possible solution would be to piece in a 2.5" Xpipe rather then an Hpipe to your collector. Then on to your new exhaust.

As others have pointed out, those 4 bolt collectors are a sure sign of these being some pretty old headers. I believe Appliance Headers went out of business in the late 70's. Also they were NOT a high end header company. They were budget headers. It's hard to find collectors that will bolt to them. I believe Hedman makes a universal 3/4 bolt combo collector. But - why. Given their age, I would assume that they probably are leaking from the flanges up top where they are bolted to the heads, and/or rusted out due to condensation. You may what to just replace with something that might be easier to pass inspection where you are located.
Also - it's highly unlikely for 390 headers to bolt to any other engine family. I'm assuming you don't have an FE in your car.

I can see from the original photos that they must have been white, so it matches the appliance headers. For nostalgia reasons, something like this would of course be great under the car. However, I wanted to have the car as a factory condition model. Do you have any recommendations for a new header that is similar to the factory and has good performance?

I am happy with the Sanderson block hugger headers that I installed on my 351C. My engine builder (same guy that built my 770HP Chevelle big-block) preferred long tube headers, he felt the short tube headers would hurt the HP. I had long tubes on my 73, and I remembered the problems with speed bumps and other road hazards. I also wanted the appearance of the engine to be as stock as possible from the outside. I originally wanted to go with factory manifolds, but could not find a nice set of correct manifolds at the time, so I decided to go with the day 2 look. My engine is a milder build because I wanted good drivability and was not terribly concerned about HP. I was more focused on the engine being able to create enough vacuum for the power brakes and A/C controls to function properly. My engine builder predicted the engine to be 440-450 HP originally but said the short tube headers would lower that expectation. I was okay with that and went with the Sanderson's. The engine ended up pulling 437HP and 451 lbs. of torque. That was close enough to the original goal for me and plenty to get the car to car shows and light up the tires every once in a while. The engine installed easily with them mounted (we left stamped valve covers on for install) and I like the way they look. I am happy that from underneath, you don't see the collectors hanging low, for my milder street build they fit the purpose. If I planned to race the car, then every bit of horsepower would be precious and I would have gone with long tube headers. I would want to get all I could out of the engine, but then the engine would have been built differently from the beginning if I was planning to race it, haha.

If you go with headers get some stage 8 locking bolts. https://www.stage8.com/ They keep the header (or other) bolts from loosening. Worth every penny of cost and time to install.

will e said:

If you go with headers get some stage 8 locking bolts. https://www.stage8.com/ They keep the header (or other) bolts from loosening. Worth every penny of cost and time to install.

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Very cool bolts! I was not aware such a bolt existed. Thanks for posting.