Langdon Headers & Exhaust measurements

[Bryan]

Was test fitting my dual Langdon headers to see how they fit and if any problems with fuel pump. For me, 1 to 1 1/2" is a little too close. Reckon I'll go the 6V electric fuel pump route. Didn't want to find out after I got my motor back months from now.  Anyway, measured all the way back to rear bumper.   Distance between header flange and block is 3 1/2" front, 4 1/2" rear.  The downpipe up front probably needs to go about 5-6" down to a curve since I'm going to join both exhausts into a single Y. Rear looks to be 7- 7 1/2" down.  Between the header pipe centers is abt 16 1/4".  Looks like I have 5 1/2" between frame and bellhousing.  About 9-10" length to put the Y in.   Distance between floor and top of cross member is 4 1/2".   It's 28" from center of cross member to front of heat shield, or 30" if you measure from front lip of cross member.  Heat shield is 20" L and 9" wide.   The flat area (some angle iron piece on side) for a muffler is 29" long.  From that angle piece to center of axle is 30" (or to hanger is 28 1/2").   Tried measuring from front of cross member lip at bellhousing to same hanger  - measures 5ft. From bottom side edge of heat shield to bottom of frame is 3 3/4".   From rear of axle to end of bumper is 47".

 

 

 

 

 

 

 

 

 

Edited December 11, 2021 by Bryan
Some pictures doubled..

[47 dodge 1.5 ton]

There are several different style mechanical fuel pumps for these engines that you may want to look at. I have a set of his headers mounted on a 25” motor in a truck. The drops are entirely different from what you have. Both are closer to the oil pump. I didn’t feel there was adequate distance to the fuel pumps I tried so decided to go  with an electric pump as well. 
  On other point you may want to pay close attention to is the mounting flange thickness to the intake you are using. My intake was .159” thicker at the flange so I machined “step” washer tabs, a little larger for better contact. Also, check and make sure there is no contact to the intake /header that would allow a vacuum leak (minimal grinding was required for my application).

  I can’t be of much help to your final exhaust fitting but glad you can still use the heat shield. 

Edited December 11, 2021 by 47 dodge 1.5 ton

[James_Douglas]

I am working on my prototype block now on the engine stand and I also noted that the flange was different. I to am making up a set of stepped washers for the attachment. My only thought is do I make them out of steel or bronze to allow them to move with the heat-cool cycles like the factory did on the outer studs?

 

I am going to use my Edmund's manifold so it will move a fair amount.

 

For the exhaust, I plane on wrapping the first 2 or 3 feet of the pipes with header wrap.

 

James

[Plymouthy Adams]

I was faced with similar scenario for the Austin build with steel flange header and the aluminum intake.  Factory being equal distance both pieces but aftermarket slight variance.  I used what is called a YOKE washer and chose for my application those that are common to the Datsun engines of the 260 and other fame.  the cupped washers are steel and very thick and could well be a source for you application....the follow is just a quick link to show you the image and where and when or even if you buy is your shopping 'call to'

 

Datsun Exhaust Manifold Yoke Washer Set, 240Z 260Z 280Z 280ZX, 1970-83, OEM NEW! | eBay

 

 

[James_Douglas]

Thanks for the info on the Yoke washers. My sense is that the washers will have to be "wing" shaped to deal with the Edmond intake and the Cast Exhaust. I also noted that the two sides may well need to be different due to casting irregularities. Some slight core shift I suspect.

 

James

[47 dodge 1.5 ton]

Maybe I shouldn’t post my thoughts on here about thermal expansion. I will say that in my experience with various alloys that it is my opinion bronze/brass was selected more for less chance of rusting in lieu of “flexing with the manifolds”. I machined some from bronze and (2) from carbon steel for comparison. Since I will keep an eye on the torque value over time, I can report my findings in a few years.

Edited December 14, 2021 by 47 dodge 1.5 ton

[James_Douglas]

MOPAR used the brass washers only on the two far ends of the exhaust/intake studs. I know some people with Chrysler Eights that have had manifolds crack when someone left off the brass washers on the far ends and replaced them with steel ones. In fact the manifolds themselves are a three part interference fit that is wedge shaped and is supposed to move. Ones that rust and don't move crack.

 

So in general I agree with you on the thermal expansions thing when it comes to thick heavy cast iron that is subject to extreme cycling from exhaust heat I think we will disagree on this one...

 

James

[Dodgeb4ya]

Wish I knew of a easy safe way to separate those three piece eight manifolds...blue tip or wedging is kinda dangerous. 

[47 dodge 1.5 ton]

1 hour ago, James_Douglas said:

MOPAR used the brass washers only on the two far ends of the exhaust/intake studs. I know some people with Chrysler Eights that have had manifolds crack when someone left off the brass washers on the far ends and replaced them with steel ones. In fact the manifolds themselves are a three part interference fit that is wedge shaped and is supposed to move. Ones that rust and don't move crack.

 

So in general I agree with you on the thermal expansions thing when it comes to thick heavy cast iron that is subject to extreme cycling from exhaust heat I think we will disagree on this one...

 

James

Don’t think we disagree as much as assumed. One large benefit of using Landons headers is not having them bolted directly to the much cooler intake noting that may cause other issues to address with temp/humidity changes. I think another important observation worth mentioning is the design of the original washer which may have allowed more pressure on intake with less torque applied to the fastener(just a thought). I did choose to use the bronze fasteners on the ends.

Edited December 14, 2021 by 47 dodge 1.5 ton

[49D-24BusCpe]

9 hours ago, James_Douglas said:

Thanks for the info on the Yoke washers. My sense is that the washers will have to be "wing" shaped to deal with the Edmond intake and the Cast Exhaust. I also noted that the two sides may well need to be different due to casting irregularities. Some slight core shift I suspect.

 

James

 

[49D-24BusCpe]

James,

 

    This is what I did on my DeVal long block engine, mounting the A-o-K tri-power aluminum intake and the Langdon cast iron split manifolds. I used a Vintage Power Wagon's Intake/Exhaust Manifold Mounting Kit AND Slant-Six spanner washers. I haven't had to touch them in three years!

 

Walt

 

 

  

[Bryan]

On 12/11/2021 at 3:21 PM, 47 dodge 1.5 ton said:

There are several different style mechanical fuel pumps for these engines that you may want to look at.

They would have to be pretty flat to increase that 1/2" of distance from the pipe. 

[47 dodge 1.5 ton]

Agreed, I saw pictures that showed much more clearance though by someone on here(may have been sniper). I was trying to search back on here around the beginning of 2021 when I was asking the same questions. 

[Sniper]

Twasn't me, I haven't mounted mine yet. 

[Bryan]

1 hour ago, Sniper said:

Twasn't me, I haven't mounted mine yet. 

The reason I was mounting mine to test is I didn't want to get the engine back, have all the other work done, and then find I need to order an electric pump, misc exhaust parts, etc and have to wait weeks.  I did call my muffler guy today and ask him if he could flare 304 stainless exhaust tubing. He said maybe but it has a tendency to crack.  Was hoping to get 304 stainless from the headers all the way back (maybe skip the muffler and go aluminized).. It's hard to find prefinished header extensions in stainless with a flare. 90 degree tubing bends are plentiful.

[47 dodge 1.5 ton]

[47 dodge 1.5 ton]

This is 49d-24BusCpe’s picture he posted a while back showing fit up. I believe this is a 25” motor and the headers are made a little different from 23” motors. Maybe he can fill in the details! 

[49D-24BusCpe]

'47 Dodge 1.5 ton',

 

    You are correct, sir! My DeVal is a 25" engine, being basically an enhanced Chrysler Industrial IND-32.

 

Walt

[Bryan]

Looks like they were designed to go with triple carbs.  4 in the middle go straight down. All the exhaust pipes are spaced evenly away from the 3 intake humps on the bottom.

[49D-24BusCpe]

Bryan,

 

    Right up front, I want to tell you that I'm a long-time friend of (fellow Michigan Hot Rod Association member) Tom Langdon.

 

    Tom's market scope for his 25" 'Spitfire' headers was for engines with "all known inlet manifolds"! In fact, I lent him my Factory Truck Dual 1 BBL set-up, to see if it was compatible with the headers he was developing. Plus we all know now, that various tri-power intakes also work!

 

    I copies the 'SPITFIRE' Headers announcement below, from the Stovebolt website this morning.

 

Walt