Dougs Headers in 72 Pontiac LeMans

[Adam07]

I am in the process of getting my 72 LeMans back on the road after sitting in storage for 12 years. I am starting this thread to share my experience with these headers and with the company.

Starting at the beginning, last year while rebuilding the Pontiac 400 in my 72 LeMans, I purchased a set of Flowtech headers to replace the rusted and crushed Hedman headers that had been on the car since I bought it. In order to clear the brake distribution block, I had to put a sizable dent in one of the tubes. I also had to remove the bracket holding the distribution block to the frame. All of this gave me marginal clearance, and I was not comfortable having an exhaust header so close to the brake distribution block. I was concerned that it could potentially boil the brake fluid and prevent me from stopping.

So after doing some online research and talking to others, this May I purchased a set of Dougs D-590 uncoated headers. I installed the passenger side first, and they fit perfectly. I thought it would be smooth sailing to install them on the drivers side. Then I ran into clearance problems. The two center tubes hit the crossmember where they turned back coming out of the head. I contacted Dougs, and was told that it must be my motor mounts (even though I had replaced them last fall). I contacted Butler Performance and Tin Indian performance to see if they had ever seen this issue. Both shops said they have used this same part number many times without issue. Jim Butler recommended trying to raise the engine on that side and lower it back down to see if it would reposition at all. This was unsuccessful. I purchased a set of polyurethane motor mounts from Butler Performance, as they added 1/8" to the height of the engine. This did not solve the problem either, though I stuck with the poly mounts for reasons I'll get to later. I again contacted Dougs to see if they could exchange the drivers side header. They said they could, but I had to pay to ship the old one back, which would up being $120. The new drivers side header arrived a couple weeks later, and fit exactly the same way.

Though I could have returned the headers and tried a different brand, I did like several aspects of the Dougs headers and decided to press forward with installing them. They have a thick flange, which should help with gasket seal, and they are made of thick wall tubing. They also do not hang low below the car, and the tube routing satisfactorily clears the brake distribution block. So I reluctantly got out the torch and hammer to dent the tubes. After denting the center tubes, the test fit revealed interference with the lower control arm mount, lower control arm, and a brake line. At this point I was furious, but resigned to installing these headers. I put 7 dents on a $559 set of headers (after $150 for poly motor mounts and $120 return shipping). These headers are a close fit, but not an exact fit. Most of the dents are less than 1/4" deep, and since I don't plan to race the car I am not worried about max performance. But I am not happy at all with the product or the service I got from the company. I am glad I bought the uncoated version and didn't have to dent coated headers.

I thought about taking the poly mounts off and getting my money back for them, but when I started the car and saw how little the engine rocked with the poly mounts as compared to the rubber mounts, I decided to keep them. I don't think I will have to worry about any of the dents not providing satisfactory clearance while the engine rocks under torque loading while driving.

Though i I have talked to people who successfully used this specific part number from Dougs, I cannot recommend it to anyone based on my experience. For the trouble, I think you're better off modifying a cheaper set of headers to fit your application.

If anyone else has a similar experience, please share it here.

[Adam07]

Here are some photos to illustrate my previous post. You can see the interference of the center tubes with the crossmember, and what the headers looked like with the dents before I installed them.

[csouth]

WOW!... That is a lot work to fit a set of headers....

[Gratefuldiver]

That's crazy you had to do that. You said you have a 400 in there. Are you sure the motor mounts (frame side) are in the correct location? There are a couple sets of holes. I had move mine and reinstall because of a similar problem. I have photos of the correct location even though its a little late. I see no reason you should have had to do that to the header. I run Hooker SC and had little to no issue with the install. As for the proportioning valve I made up my own bracket and relocated it to the top of the frame vs on the side. It fixed all the clearance issues with the headers. It was also close enough to the stock location that my stock lines still worked.

Ive had my car apart many times over the last 25 years, so if you have any questions Id be happy to try to help!

[Gratefuldiver]

Come to think of it, my buddy with a 72 Lemans installed those same headers and no issue besides PV relocation.

[Adam07]

It's been over 2 years that I've been running these headers, and I haven't had any further issues with them. Yes it was a lot of work to fit a set of headers, and they really shouldn't be as beat up as I had to make them to install them in the car.

I did a lot of thinking about modifying the motor mounts, but decided against it because I felt it would be more work than denting the header. I also questioned the long term reliability of home brew motor mounts. The Butler Performance poly mounts have been working well. I've had the cylinder heads off the car twice in the last two years, once for valve guide replacement and once for a head gasket. So bolting and unbolting from the heads has been straight forward. I'm running the gaskets Dougs supplied now, and they seem to seal better than the stock steel gaskets I used initially.

I would still caution people looking to use these headers in a similar application. I saw at least one other person have the same issue on a Pontiac forum. So there has to be something about the mounts, mounting location, and block that occasionally causes this issue. No one has been able to definitively say what the problem is, so I would say buyer beware.

[CampbellshotrodsAZ]

Hmmm, that's interesting. I'll be going the same route, but in a 71 Firebird so hopefully I don't have that issue. But I think Doug's is otherwise the best header out there, so I'll risk it.

But if it helps, the dents won't hurt performance. Look up Engine Masters on Youtube, they ran several dyno pulls on the matter and it didn't hurt performance, actually helped up to a point!

[Adam07]

I can't vouch for using Dougs headers in any other vehicle, but I chose them initially because they got rave reviews everywhere. I only found one other person on a Pontiac forum who had the same problem with the same part number and a similar car.

My car is mainly street driven so I don't really worry about the performance aspect of the dents. I was just really disappointed to spend the $$ for Dougs headers over others to have them fit poorly like that. But I stuck with them because of the thick wall tube construction and the fact that they don't hang low.

[Shawn01754]

On a side note there's a company selling stainless steel headers for our round port head cars. They are almost identical to doughs in shape and half the price with awesome flanges, beautiful finish and never rust. I've been running them for 3 year. My headers we a chore and had to move my brake dis block. In fact I used Dougs installation instructions because they didn't come with any. All the pic I had seen, the headers looked like a duplicate except these were stainless. http://m.ebay.com/itm/OBX-Header-Man...-/181799785433 Also, I used to tear motor mounts all the time with my 400hp motor. When I dropped my 600hp motor I installed butler motor mounts and never had a problem awesome investment. Did you inspect your motor mount bracket that mounts to the frame, that will create the motor to sag if it's worn. Did you inspect you tranny mount?