Yep, I saw a '65 GTO with Doug's headers on round port E-heads over the weekend. It had the dimples, too. They seem to appear less noticeable once installed.

I'm finally installing my Dougs on the '67 GTO w/E round ports since I could not get the RA manifolds. They clear the block, motor mount, and bellhousing well, but on the passenger side you can see the #6 tube is right against the frame at the top at the radius of the frame where the blue tape is. I really do not want to ding it and I have not fitted the driver side yet per instruction to do Passenger first. The mounts are "new" NAPA and have been sitting in the box for 35 years. If I were to put a washer under each motor mount bolt between block and mount it would move it over enough, but I think I should test fit the driver side first to see where I am. Anyone else have this problem? Body is of frame now as well. Had to move a brake line slightly and if the engine moved to the drivers side just a bit it would work great. Also have the 1/4" spacers under the frame mounts so the Canton oil pan would clear the center link. Also those are remflex gaskets (.160") thick vs the suppled Doug's gaskets which looks like about .060" thick. That will be my first try here with thinner gaskets. That .100' might do it.

Not sure if that washer idea will cause me other problems.

And ZeGermanHam - mine have the dimples for the bolts as well.

Feedback & experience appreciated.

https://live.staticflickr.com/65535/...9f397ba7_c.jpgDougs install 1 by Matt Fronk, on Flickr

Update - thinner gasket did not help. Installed driver side and plenty of room along the frame rail but will require a little grinding on the lower control arm support. See the two pictures. Looks like engine needs to move toward Driver side a bit, grind some clearance on driver lower control arm mt and passenger side will be all set.

Anyone else need to shift engine over like this on a 54 yr old car??
Thanks

https://live.staticflickr.com/65535/...d18bf3ac_c.jpgDougs install 4 by Matt Fronk, on Flickr

https://live.staticflickr.com/65535/...9ef98eb7_c.jpgDougs install 3 by Matt Fronk, on Flickr

With your 1/4" spacers under your frame mounts, the engine shouldn't be sitting too low, but out of curiosity, did you confirm your motor mounts meet the minimum height as specified in the Doug's install guide? I only ask because people used to have so much trouble with aftermarket motor mounts being dimensionally incorrect in the past. Also, can the frame mounts be loosened and moved a tad to the driver side?

https://i.imgur.com/ynT88i5.jpg

Yes the measurement is right at 1-1/2" so we are good there.

The frame mounts were pretty tight on the bolts as I remember. Fortunately the body is off the car so it is pretty easy to pull these on and off. I'm going to try some shims under the pass motor mt to block interface and see if that will move it over and see what the pass side looks like. I have see others have to grind that lower control arm mount to get some clearance.

The up/down is not the problem - it is side to side. I'll keep all posted on outcome in the case it helps someone else. I'm wondering how those Ames torq lock mounts might work if anyone has expereince with them?

I've got the new "Torq Lok" motor mounts from Ames, but unfortunately the engine is still out of the car. What I can say about them is that they measure 1-9/16" when measuring from the locations specified in the Doug's guide. So, they're 1/16" taller than what you have, which is probably not enough to make a difference.

https://i.imgur.com/zF94Xskh.jpg

If anyone doesn’t want that dented up look .I know tubular automotive in mass (they made many header companies Pontiac headers as a wholesaler) makes nice round port IV firebird headers

And mad dog makes some beautiful headers they made a set for me and they are top notch haven’t tried them in the car yet but the quality of the build is really nice.

New Doug’s headers
 

I put headers on my 65 GTO and that was the first and LAST time I will do so. This thread reinforces my decision. It is pathetic to me that a company would even release a product that looks like this. Unbelievable to me that they apparently aren’t skilled enough or professional enough to come up with a more elegant solution to these figment issues, especially considering the prices they have the nerve to charge for their “cobbled together” looking stuff.
More power to the rest of you guys still willing to fight this fight.

My super comp D ports on 68 bird had a couple similar dimples...brand new 1 & 7/8" doug's are the same.

Yep, it turns out Doug's are not the only headers to have these dimples for bolt clearance. It seems like it's just a byproduct how header primary tubes need to be routed to fit in Pontiacs. I'm not going to lose any sleep over it.

What is the part number? D567? If so I've had a set since for years and don't have those issues! How thick is the flange at the heads? Mine measured 7.45 MM.

Jake

I'm watching ths thread with great interest, as I will likely be going with the Doug's round port 567's also. I see on their website that the flanges are 3/8", or .375", which is 9.525mm

I am NOT happy with my last set of Doug's 522 for my 71, had to massage them in a couple spots, are so close to the frame in a couple others they contact on uneven surfaces while driving, the collectors did NOT point straight back, and were different heights.

Sadly, with less than 1k miles, I'm going to have to replace them. Super Comps for me next, fingers crossed.

.

Jake the spec for the D567 says the flanges are 3/8 (.375"). I measure .400" (10.16mm compared to your 7.45mm) plus the head side of the tube is proud of the flange by a bit as well. This could be some of the issue pushing the header toward the frame? This would certainly rotate the header away from the frame if the flanges was thinner, etc.

To make them work the driver side was ok after I ground off part of the lower control arm mt. The passenger side took some fiddling as it ran down along the frame on the one tube shown in my post. I ended wrapping the tube in blue painters tape, put a red shop rag on it and then used a 1 inch wide pc of aluminum 1/8" thick and 2 ft long. I laid the Al pc on the shop rag and with a small 5lb sledge flattened the tube so I had about 1/4" clearance. It made me sick to beat on the $800 headers, but they are in place now. Pass side lower control arm mt needed some clearance as well for clearance there.

I tried the AMES new mts but they were too tight to go over my frame mts. I had "new" NAPA mts I bought 30 years ago that fit fine and I added the ram air battery cable pc to the driver mt - took some fiddling as well. I have about 1/4" between worse pipe to frame on either side-hoping this is enough. Will put a strap on the engine I'm sure.

Hope this helps those who are starting on this - glad the body is off the frame. Now working on the Pypes exhaust system and wrestling with this with no body on as well.

The block is a '70 with 72cc E-heads. I wonder if the exhaust flange on this head is in the exact place as the RA4 heads?

And this method of Dougs header adjustment did not damage the coating

FWIW, I measured the flange on my Doug's D-port D564s tonight, and it measured at 10.21mm. The engine's not in the car yet, so time will tell.

My Doug's D567 have 1 3/4" tubes and 3" collectors, not 1 7/8" tubes and 3 1/2" collectors as in this ongoing post. I believe I purchased then in 1974 to put a Ram Air 4 in my 67 GTO, cost at the time: ($150.00) Only issue I had was having to move the brake distribution valve out of the way on the frame. Regular size oil filter can't be removed without taking all the bolts out of the right header and collector, makes a slight mess.
As I noted earlier the flanges are not 3/8" thick at the heads!!

Mine hit exactly where you listed, cannot install engine until we clearance them. I have the mounts shimmed, and the headers would not ever fit without them. Also, have E heads as you do. Brake line has to go in front of the cross member as the driver's side almost sits on it. my original D567 from 1973 fits easily, the thicker flange and the larger tubes are the problem!!

Should flange thickness even matter, though? As I understand it, the primary tubes extend through the flange, so in theory the flange itself does not determine how far off the exhaust ports the header ultimately sits. I'm guessing it has more (i.e., everything) to do with the larger 1-7/8" primary tubes you have with the D567 units versus the 1-3/4" primaries on the D564s.

Doug's header fitment D567
 

I believe you're correct about the flange thickness, as it appears the tube for #6 cylinder lays on the frame as shown earlier.
New mounts (Butler), spacers under mounts, new poly frame bushings and passenger brake line removed!
This has been an absolute horrible installation. Will have to dent or massage #6 tube to install the gasket!