Made my own down-pipes for Hedman shorty headers

[MopaR&D]

As we all know when it comes to V-8 exhaust on A-bodies things can be a real pain unless you drop big $$$ on TTI or Doug's headers. One lower-cost option is the Hedman Tight Tubes which is a shorty/block-hugger design. They fit great but the issue is the outlet location; it faces straight down and is only inches away from the steering linkage. When I first put mine on I had it hooked up the best way it could at the time with the pipes going under the drag link. Of course after only a few hundred miles the pipes got smashed up pretty bad to where they were not more than 1 1/2" wide which obviously restricted flow.

Recently when I went to swap my rear axle to an 8 3/4" model and pull my trans for a TC swap I decided to drop the exhaust and see what could be done. After laying under the car and looking at the situation for a long time I figured the downpipes could be made to go up and over the linkage but the bends would have to be SUPER tight. I took a trip to my local racing parts store (OnTrack Performance off Santa Fe/Dartmouth in Englewood) and had a EUREKA! moment when I came across this:

These are exhaust "donuts" made by a company called Pro-Werks. I'm not sure how they are made but they have a radius of curvature basically the same as the diameter of the pipe itself; literally the tightest bend you can physically have on a metal pipe. I also ordered a set of Sanderson angled collector reducers and got to work slowly mocking up, marking, and MIG-welding the sections together until I came up with these:

 

[BigBlockMopar]

Are these the same shorty headers as you have?

I will be tackling the same deal pretty soon but haven't really been able to make a mockup as of yet, but reading your story I'm not looking forward to it.

Couldn't you just pie cut the headercollector and angle it a bit in the right direction first, before making the snake-downpipe?

 

[360Scamp]

Cant wait to see them installed, I have long tube headers on my Scamp and the driver side is smashed flat and Im getting ideas once I figure out which direction I want to go

 

[Woods74]

Cool, keep us updated on progress!

 

[Treblig]

I had the same problem with the 340 manifold on the driver's side of my '69 Barracuda (318), P/S, 2004R transmission with TCI adapter). I ordered some super tight radius J-bends (see pics) and cut the J-bends up and pieced it together. It took a lot of time but it wasn't too hard. It would have cost a fortune to have the muffler shop build this pipe system. I had asked the muffler shop (last year) to use 2 1/2 down pipes and never looked at them after picking the car up. When I installed the 2004R transmission I found that they had used 2 1/2" on the passenger's side but because there was so little room on the driver's side they used 2 1/8" with no mandrel bends so it was pretty bad. If I had known about the super tight donuts I would have bought one. The donuts look even tighter than the ones I bought even though the ones I bought had the tightest MANDREL radius I was able to find on the internet.
But your job turned out nice and you'll have very little restriction. Building your own isn't difficult but does take a lot of time.
Most muffler shops don't have the machines capable of making the mandrel type bends and super tight radii so if you don't do it yourself or pay some pretty big bucks to a upscale muffler shop you're just out of luck!!


Treblig

 

[txstang84]

There's a 7 or 8 page thread in the exhaust section about those headers...I have them installed in my Scamp as well...I bought some mandrel 2.5" U bends from Columbia river mandrel bending and had my exhaust shop weld up the sections with the same idea in mind...I think the pics I posted are on 6 or 7...

 

[MopaR&D]

They have actually been installed on the car for a few weeks now, I'll grab some pics under the chassis. Feels like I gained 40 HP on the top end BTW just like I had hoped, this setup is much less restrictive than the old pipes; my 360 used to run out of breath around 5000 RPM but now pulls hard to 5500. I'll get a pic of the old junk as well just to show the difference lol...

 

[ir3333]

...i'm sure Tom Swope could build a down pipe for these.
...another option would be to re-flange the header at a bit of an angle.

 

[Treblig]

...i'm sure Tom Swope could build a down pipe for these.
...another option would be to re-flange the header at a bit of an angle.

I've done that before!!! I used a reciprocating saw to cut a pie slice out of the collector leaving just a little attached. Then bend the collector to close the gap and weld. You can change the exit angle quite a bit but if you go too much you start hurting your flow.

Treblig

 

[MopaR&D]

I've done that before!!! I used a reciprocating saw to cut a pie slice out of the collector leaving just a little attached. Then bend the collector to close the gap and weld. You can change the exit angle quite a bit but if you go too much you start hurting your flow.

Treblig

I realized this as well but was too scared to cut my headers, it's definitely a good way to go though.

 

[MopaR&D]

Here they are on the car, obviously I didn't cure the pain right as it is already peeling but I kind of expected that haha...

 

[Treblig]

Here they are on the car, obviously I didn't cure the pain right as it is already peeling but I kind of expected that haha...

Looks good but don't know if you noticed....You have a small exhaust leak at the first pipe clamp on the passenger's side. Don't know how much street driving you do but you might get some exhaust in the car from the leak. That's one good thing about the yellow...it shows the leaks REAL GOOD!!!

Treblig

 

[MopaR&D]

Yeah it's still kinda "thrown together" at the moment, I haven't tightened down the clamps fully as the pipes don't fit quite as snugly as I'd like.

 

[Abodybomber]

Yeah it's still kinda "thrown together" at the moment, I haven't tightened down the clamps fully as the pipes don't fit quite as snugly as I'd like.

You noticed a difference Kid,the difference is your knowledge,effort & improvement. Nice find.....