I've an old set of old Doug Thorley headers on my bird, want to get a new set of long tube ceramic coated headers. I found the Doug's Headers D569 ceramic coated ones. Can someone who has these on his/her car tell me how they fit and if they hang down, what clearance is like? Mine is a Pontiac block, power steering, non boost manual brakes, standard transmission floor shift.

I had to remove some of the clutch linkage to get the thorleys off and on as well as bash, I mean massage the pipe to clearance the steering box. Don't want to bash a new set.
Thanks

Sent you a PM. I like dougs but then these are the only headers I’ve ever had.

Al, I just put them on when I installed my engine and they fit good. They wont go on without raising the engine up an inch or two and they hug the floor board nice and tight. The bolt pattern where the collector bolts onto sits about 1/4 inch from the floor board. I have the round ports Doug's and auto trans and these headers do not contact anything but it is tight around the steering gear box. No banging and beating to make them fit.

Thank you,
Did you raise the engine then lower it once again after they were installed? Do you think the header flange so close to the floor will transmit heat up into the floor and cabin? How close do you think the pipe is to the steering box, 1/8, 1/4, 3/8,...?

Anyone install the Dougs D ports?

Had to move one of the tubes on my friends 69 bird on his Dougs headers on the drivers side. the steering arm was making contact and limiting the full turning radius.

I actually was installing the engine at the same time, but yes I had the engine sitting on the mounts and then raised it back up about two inches placed the headers up on the engine and put a couple header bolts on and then placed the engine back down. I am sure that there will be a little heat transfer to the floor but never had these before so I have no idea how much if any will transmit to the cabin. The third tube back is about 1/8 of an inch away from the steering gear box and the second tube is about 1/2 inch away from the box.

Thanks guys.
1/8"? Crap, that's about what mine was before I bashed it. My power steering fluid got so hot it peeled the paint of the pump reservoir. I bashed the pipe then put in a cooler and it's been OK since then. How about the oil filter, good clarance there?

Moving one of the pipes, did you get them
recoated after cutting and rewelding the pipe?

they were not coated headers
ill see if i can find the pictures so you can see the difference.

I have plenty of room to remove the filter, I will try and snap a pic or two. Obviously that depends on the size of the oil filter but the one my engine builder recommended. My steering arms does not even come close to making contact with the headers.

Hmm, steering arm on a 69 the same as a 67-68?

Do you have aftermarket heads that require round ports or stock Pontiac round ports? I'm wondering if the E heads have the exhaust port surface at a slightly different angle than stock pontiac heads. Do you have stock engine and tranny mounts or aftermarket ones that could be thinner of thicker than stock?

I think none of these sets of headers are the same. especially if they were made over the span of 10 years or so. They may be the same part number, but they are not all built the same exact way.
I have hooker super comps that i can get in and out without doing anything and there is plenty oil filter clearance. But then you hear guys with the same set of hookers have problems. they have to be made differently in some way.

Yea, I suppose the tooling could wear and the personnel could have different ideas on what is quality work.

You'd think if a header on an engine on a stand would clear the filter in 2009 the same header built by the same company/factory in 2019 would at least be close enough to clear the filter. Parts of the car are a different thing. Motor/ tranny/body mounts saging, new or replaced with aftermarket, can alter the position of the engine in respect to car parts. I couldn't find much searching for this here, but I googled it and found piles of FGF site threads on this very subject, some with me posting that I forgot about. Seems a Doug's header will fit great for one guy and not worth sht for the next. Big gamble at $800+ a pop.

I posted my Doug Thorley headers fit well, they looked that way when I bought the car. After installing new body mounts, changing the transmission crossmember and mount, engine mounts, changing transmission and removing then replacing steering components the header seemed to be closer to the steering box than before. Bashing it seemed to be the only fix.

I found about fifty posts from different sites telling how the Doug's headers didn't fit without bashing the tubes and/or the floor boards or having to use a remote oil filter. Only found about 10 who said they fit right up without clearance problems. About five of those without clearance problems said "except this or except that" they have a different definition of clearance problems than I do.
More post about bad fit than good fit could be because people tend to say more about what went wrong than what went the way it's supposed to..

Don't know what to do now, not like you can go to the local muffler shop and keep trying different brands of headers until you find one that fits just right.

Went with Dougs and have no regrets. They fit tight along the floor allowing exhaust to maintain great clearance.

Great pics, Do you have one of the headers and the oil filter?

Looked at Hookers on the Holley site. Checked out the Competition and super comps.
Comps have 16 gauge 1-5/8" tubes 26" long and a 5/16" flange with 8" collector, bolts and gaskets, no reducers, ceramic coated for $625.
Super comps have the same 5/16" flange with larger 1-3/4" tubes 28" long but only 18 gauge. Larger ID than 16 gauge but thinner wall. 10" collector, no reducer, bolts and gaskets, ceramic coated for $855.

I checked out the Dougs D569 on the Butler site.
They have a thicker flange than the Hookers, 3/8". Tubes are 1-3/4" like the super comps but thicker 16 gauge steel. Doesn't say how long the collector of tubes are. Comes with gaskets, bolts and reducers, ceramic coated for $814.
Butler says a 90 degree Oil filter housing is needed.

I have E head round ports and using aftermarket Trans mount and have the Butler Poly mounts. I attached some pics that were kind of hard to get the right angles with most everything install so sorry up front if they are kind of crappy. I can tell you that my engine does not appear to sit any higher then before. I do have solid body mounts or aluminum, which ever they are.

This is my friends dougs driver side header i had to move a tube on because of interference with the pitman arm on his 69 bird.
the tube i circled used to be more straight down from the flange.

Not gonna read thru the whole thread to find out. But I assume the car has the curved V8 pitman arm ?

There are straight Firebird pitman arms?
All the Camaro ones I've seen are straight, but different engines so pipes would not be same as ours.
Is it just a 6 cyl compared to V8 change?

1969 used the straight Pittman arm
Also the center link is different than 67,68

My 69 power st has the curved arm orig I believe..

The guy wanted me to put on V band flanges on the same headers.

I like the idea of the v-bands over the usual three bolt design. That guy building the 'tribal tubes' uses those a lot.