[HWYSTR455]

Can anyone post some pics of Doug's D522 headers installed please? And general notes/comments on fitment?

Trying to choose between the Doug's and the Hooker Super Comps, fitment is my main concern. Know the D567 Doug's need doctoring, and don't have any firm data on the D522s that I can find.

Thanks a ton in advance!


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[firejunkie]

I have the 590 units, and they needed some slight massaging to get to fit. These are 1 3/4. Your looking at 2" primaries, so I am sure much more work needed. The 1 3/4" ones are tight as is. I got 430hp / 515 lbs tq.

[HWYSTR455]

My understanding is that the D522s actually require less work, and fit better than the smaller primary one. But am trying to confirm that.

I had the smaller primary round port ones and they did require some work, had to flatten some tubes to get it to clear, and had to lose the back drive linkage. The D522s work with the back drive in place.


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[PunchT37]

I had the 522`s for my new engine. I gave up on them. I couldn`t get them on the heads OUTSIDE of the car. So, I went to the 17/8 tubes. Much easier. Had some pics but can`t find. I do remember the #4 tube covering the #8 spark plug hole/exhaust port.


https://shop.dougsheaders.com/media/...5/d/5/d522.jpg

[HWYSTR455]

I haven't heard that issue before, but like I said, I did have to mod the smaller tube ones.

I'm committed, have the D522s in hand, and will do a legit thread on my experience. I looked at the #4 tube in relation to where the plug would be, and it looks like plenty of clearance. About to get out there now, should have something to post by dinner.

I already mocked up the driver side, and there's only a slight mod needed on one tube where it goes past the frame. Maybe about the size of a half dollar.

It clears, but it's so close, any engine movement and it would contact. I prefer to not have a banging sound, or spacing out the engine mounts like some do.

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[HWYSTR455]

Guess this thread is fine for posting my experience with the Doug's D522s...

Ok, so just to give all a reference, here's the car installed on info:

*1971 A-body, 2 door hardtop, originally a 350 2bbl car with an auto floor shift
*NON-AC car (came originally with AC, though did a firewall smoothy panel)
*Power Steering
*'69 block, 461 stroker, with round port E-heads
*Anchor 400 engine mounts sourced from NAPA
*Global West AFX upper and lower control arms

Out of the box, the headers looked good, no visible damage, purchased via Summit Racing, and had them in hand in 3 days.

I did a mockup of the supplied gaskets, 2 holes were kind of close, and believe I only slightly touched up 1 hole.

Although the headers came with stainless hex bolts and star washers, I chose to purchase ARP 12-point stainless bolt, ordered ones that were 1/4" longer after measuring the hole depth in heads, and didn't use washers for the install. (I can provide the exact length if desired.

I started by mocking up the drivers side, and although they fit, the #3 tube came very close to the subframe, and I chose to slightly dent the tube, roughly the size of a half dollar. I felt engine movement would have made the tube contact the subframe.

Marked the area I planned to dent, and started whacking it with a ball peen hammer (flat end of hammer). When I was happy with the dent, wiped it with acetone, and shot it with some engine paint (aluminum). The coating was slightly damaged, but it's in an area that you can't see, and hopefully the engine paint will keep it from flaking.

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[HWYSTR455]

Mocked it back up, checked the area, and whalah, clearance added.

(pics are without a gasket in place and bolts loose)

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[HWYSTR455]

Moving over to the passenger side, I mocked the header up.

Instructions included with the headers say to remove the engine mount bolt and jack engine up. Trying to install without this step failed, resorted to giving in, removing the bolt, and jacked it up about 3-4 inches.

Header went right in, and bolted right up. No mods were needed, but do have a few comments.

Obviously, as the instructions state, these cannot be used with A/C in place, since the one tube would make contact with the evap housing.

As previously commented, the #4 tube comes somewhat close to the #8 plug tip, and would require a 90 degree boot, or maybe an adjustable/vari-angle boot. The tube is sloping and the #6 plug tip would work with a vari-angle boot, even though in the pics it looks like it might require a 90 degree.

The headers hang near evenly on both sides, collector exits are pointed in the correct angle, 90 degrees to the length of chassis, clear the 4L80E pan, lower control arm mount point, and the standard oil filter housing. It appears a standard PF24 size filter will fit with no interference.

Personal conclusion: These are the best fitting headers I've ever used, requiring the least amount of 'work' to install, and feel they are quality parts. I would recommend these to anyone with a non-AC 68-72 round port application.

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[Interceptor]

Any pics from underneath? How low do they hang?

[HWYSTR455]

Originally Posted by Interceptor

Any pics from underneath? How low do they hang?

They hang very even, the driver's side is just very slightly lower, would say total below the pan (Canton Road Race) is roughly 1-1.5" max. Totally acceptable.

I will have to take a pic and post, give me a couple days, I need to push it out of the garage a little in order to get a good shot, won't have time today, lucky if I can sometime this week, probably next weekend though.

Maybe by then others may have requested additional pics too, will get them all at one time.

Like I said, these headers are the least work I've ever had to do to get a set of headers to fit. I've had Hooker Super Comps before, but D ports, and those as I recall, the passenger side hung lower. That from what I understand is not an issue with the round port ones. I suspect they are about the same fit as these (D522s). They look almost identical by photos.

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[firejunkie]

Glad they went on with only a slight mods. About what mine required.

[HWYSTR455]

Update on this install.

Got to a point where I was installing the exhaust (Pypes 2.5 with X, valance exit), and it made clear the driver's header collector exit is tipped inward (towards car centerline) about 1", maybe a tad more, and down about 1/2". Very difficult to tell visually, until you start hanging the pipes, then it becomes obvious.

Since it's off, the X pipe doesn't lay completely horizontal, and will require mods in order to do so, or the whole exhaust would look 'twisted', and valance exits would be off.

I will take the car up to have the exhaust welded once I reach that point in the build, and have them mod the pipe(s) to allow it to mount correctly. I cut 2/3s the way through the one pipe leading up to the X from the header, pushed together and welded, should correct the issue.

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