Hi,

So Dad and I are getting a MIG welder around Christmas time, the plan is to weld in the exhaust for my A body valiant. (Gasless MIG around 150 - 200 AMPS is what we are looking for).

I believe I found a shop where I can buy stainless steel piping, have it cut to any size I want, and I can also purchase bends as well.

My question is do I need any particular grade stainless steel?
What wall thickness is recommended (I am going with an inside diameter of 2.5") ?
Am I correct in thinking the exhaust should be the same inside diameter as the headers I have? (2.5")
Should I weld the headers straight onto the exhaust pipe and let the Exhaust brackets take the engine vibration or should I get one of those mesh pipes that allow movement to limit vibration at the brackets?

I plan to go headers, pipe, cat converter, pipe, muffler, pipe etc.

Thanks in advance for your help, I did look around the forum and I've been googling as well, but I would prefer to hear from someone who has done this job before.

Thanks!

If you are NOT required by law in your area to have the catalyctic converter then I'd say ditch it. Save you money and save you work. What have you done to the engine? Stock 1bbl? Did you do the super six conversion? Wall thickness is usually 18 guage and pipe diameter is "Outside diameter (O.D.)" If the car is just an every day driver with very little engine modifications I'd say ditch the header and just go with either stock exhaust or Dutra Duals (but this is just a matter of my opinion.)

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'73 Scamp (the girlfriend): 225ci super/6 2BBL conversion (Almost done!)
'90 Subaru, wagon (the wife): H4-cyl 2.2L

1977 Mercedes-Benz 300D, 5cyl diesel(For sale!)

Oh, my...

I'd have to agree.. Unless you've got a high zoot slant, you don't need headers. In fact, from everything I've been reading on this forum, unless you're going to race the car, or try and make serious horsepower, the headers are only going to kill daily driveability, because it will take forever for your carburetor (which is hanging in the wind) to warm up. There's an old timer in town here who says to run dual pipes to just under the front seat, then join them into one, and use a sixties vintage mercedes "muffler" which was actually a glasspack, and you could see through it from front to back. I think he's referring to the mufflers on the pagoda cars (230, 250, 280). You really don't want a catalyst at all. If the area that you live in requires it, get antique tags, or move away. (or I have "heard" of people who break the law by hollowing them out, but these people are awful human beings with no remorse or soul...)

Matt

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63 Valiant 200
64 Dart 270
73 Fury II
84 Cherokee 2 dr
86 Dodge W-150
73 Volvo 144
74 Volvo 145
81 Volvo 245

Headers were already purchased I have a set of pacemakers. I'm going to put in a hotbox on the bottom of the manifold, and a heat shield hopefully this will compensate.

Hot box: I was planning on a fairly thick steel box, with a copper surface top. (Again haven't looked into it all yet). Will have a inlet at the top and an outlet at the bottom that'll feed into the coolant piping.

As for engine mods at the moment, 350 holley, port and polish job, elec ignition with a module, newer coil etc. Plan is to shave the head achieve around 10:1 compression (Haven't done calculations yet), and if it hasn't been fixed for unleaded fuel I'll enlarge the valves to 1.70 and 1.44.

Thanks for the help. I believe in my area a cat converter is required. Will double check thankyou!

I have not personally run an exhaust header but i'm sure someone else will chime in the cons of running them for street use.

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'73 Scamp (the girlfriend): 225ci super/6 2BBL conversion (Almost done!)
'90 Subaru, wagon (the wife): H4-cyl 2.2L

1977 Mercedes-Benz 300D, 5cyl diesel(For sale!)

I am running Clifford headers, and to over come poor drivability from iceing I had to add some heat.


Here is a hydronic hot spot I fabed up for a Clifford intake to supply heat to intake. It solved the problem nicely.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I'm not sure you can properly weld stainless with a gasless MIG.

Usually you need argon or argon mix gas.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yeah, people use gas, a tri-gas mix sometimes. Other than that it welds up exactly the same...after all stainless steel is pretty much steel it's just 80/20, Steel/Chromium.

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'73 Scamp (the girlfriend): 225ci super/6 2BBL conversion (Almost done!)
'90 Subaru, wagon (the wife): H4-cyl 2.2L

1977 Mercedes-Benz 300D, 5cyl diesel(For sale!)

I thought you could use gas shielded flux cored wires in a gasless mig for things like stainless steel etc. Has anyone tried this? I've looked on a few websites seems doable. Would like to hear if anyone else has done it before.

Wjajr I like your design and will make something similar that I can hopefully bolt on directly.

If anyone is interested (When I come up with a design I'll make a new thread) I would happily make a few hot boxes if people wished to buy them, don't think it would be too expensive, but that won't be for a while.

I would definitely be interested in seeing what you come up with as I am also trying to design my own exhaust to (minus the hotbox.) I'm using the stock exhaust manifold.

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'73 Scamp (the girlfriend): 225ci super/6 2BBL conversion (Almost done!)
'90 Subaru, wagon (the wife): H4-cyl 2.2L

1977 Mercedes-Benz 300D, 5cyl diesel(For sale!)

I will attempt it shortly after Christmas, I'll upload some photos of how I go and the troubles I'll run into. I plan to buy parts from this site:

http://www.bestmufflers.com/bshop/index ... 5e8509b496

I was quoted around $600 to have a single stainless exhaust put in (excl manifold). I think I should be able to get it done for around $200.

You can weld stainless with flux core wirebut flux core tends to run hotter making the weld more brittle. Your welds will be more prone to cracking over time. Flux core welds dont usually look the greatest either. But if your dead set on running flux core, I'd suggest sleeving the joints first then welding the ends of them instead if a pipe to pipe joint.

There was a discussion in a thread awhile back about the dual exhaust setup for the a-body V8's. It was a complete setup from jegs.com for $205 designed for headers. The discussion was about using one side for a slant six so for $205 you get TWO complete slant6 exhaust setups.

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'73 Scamp (the girlfriend): 225ci super/6 2BBL conversion (Almost done!)
'90 Subaru, wagon (the wife): H4-cyl 2.2L

1977 Mercedes-Benz 300D, 5cyl diesel(For sale!)

Tube is measured OD x wall thickness. Pipe is measured in nominal sizes. Neither here nor there though; I just like it when I actually know something about what's being talked about.

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65 4 dr. Valiant 200

Yeah, its kinda' like when someone goes to HF to buy their hydraulic pipe bender to use for rollbar or exhaust tubing and wonders why it wrinkles the bends. In the industrial world, pipe and tubing are two different things and are measured totally different in size, so make sure you are clear on how you are classifying what you are needing to the company before you buy it. It can save you a lot of expense and headache.

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There's no such thing as too much cam....only not enough engine!