69 Firebird Headers sitting on Steering Gear box

[AM.MSCL]

I had a friend notice a banging noise in the engine bay of my 69 Firebird. He determined it was only at idle because it went away when the rpms increased. I got to looking around and the Doug Thornly Headers on my 400 cubic inch engine are touching the power steering gear box.

Would new Poly motor mounts help with eliminating the banging at idle or no?

Thanks
Ray

[chevnut55]

i had the same problem,yes the bushings will help,i had to mark it and dent it with a hammer.it does not hit anymore,but the headers are low to the gound and hit sometimes.there has to be better firebird headers out there.

[wmhjr]

i had the same problem,yes the bushings will help,i had to mark it and dent it with a hammer.it does not hit anymore,but the headers are low to the gound and hit sometimes.there has to be better firebird headers out there.

There are. Dougs. Not Doug Thorley. Different headers. WAY better and tighter fitment. The low exhaust port geometry on Pontiac heads can be real problematic.

[T_Raven]

There are. Dougs. Not Doug Thorley. Different headers. WAY better and tighter fitment. The low exhaust port geometry on Pontiac heads can be real problematic.

Good to know, I always thought they were the same.

[DynoDon]

Common misconception. The Original Doug's Headers is a different company than Doug Thorley Headers. The company started out as Doug's Headers (AKA Headers by Doug). As time went on Doug started to use his full name - Doug Thorley Headers. But soon after he and his wife split and Betty ended up with Doug Thorley Headers and Doug was really involved. Betty and here partner ran the company with their own designs and mainly concentrated on the Motor Home and truck markets. Doug restarted his own deal under Doug's Headers and concentrated mainly on the muscle car market. After Betty passed away Doug Thorley Headers was sold to a company that also owns Jardine Headers (which is motorcycle oriented now, not the drag race/muscle car headers of days gone by). Doug continued with Doug's Headers until he decided to retire and sold the company to PerTronix about 5 years ago. We continue to make Doug's Headers from the same fixtures that Doug originally made along with many new additions over the years. We also own and manufacture Patriot Headers (the old Ermie Immerso company) Thunderbird Volkswagen Headers and two years ago also bought JBA Headers.
There's your history lesson for today :twothumbs:

[AM.MSCL]

I guess I better check to make sure which brand I have but the issue still remains that the driver side header is touching the Steering gear box.

[wmhjr]

Yup, very different. There's more interesting info about the history of all the header companies. For Pontiacs, Dougs are universally considered to be the best fitting. Now, to be completely honest I'm not very favorable to the "factory" ceramic that Dougs/Pertronix does. I personally returned a set of coated Dougs and replaced them with a set of Dougs that were coated elsewhere. That being said, I know I'm picky.

Also, on my ride even the Dougs are low, and can scrape easily. Of course, that's more because the entire car is lowered. All the SC&C magic stuff. The headers are just a bit lower than the engine crossmember. The car IS low.

[wmhjr]

I guess I better check to make sure which brand I have but the issue still remains that the driver side header is touching the Steering gear box.

That's bad juju as far as I'm concerned. In addition to the obvious, you're likely cooking that box pretty good as well. I'm not sure how well different engine mount bushings will help. To me, I would assume that "at rest" the motor touches the box, which is why at idle it's making noise. At higher RPMs the motor is torqued a little, creating a bit more clearance. So, if you put poly bushings they're stiffer, keeping the motor in the "rest" position more frequently, possibly INCREASING the contact. I dunno for sure.

Me thinks fixing the header fitment itself may be required regardless of swapping to MityMounts or similar poly engine mounts. The MityMounts don't change engine position.

[DynoDon]

I guess I better check to make sure which brand I have but the issue still remains that the driver side header is touching the Steering gear box.

To be honest, back in the 70's when the headers you have were designed (regardless of brand) most header designers didn't worry a whole lot about headers doing things like hitting steering boxes or frames, especially with a lumpy cam. I assume it's not resting against but rattling on it as the motor moves. It was just considered something you lived with in exchange for more power. Ground clearance wasn't an issue either - many guys used to laugh about scraping the collectors on speed bumps.
Today's customer is a bit more demanding and cars are being lower to heights we never thought of back then.
The other issue is these cars are now 40 years old and just like us, things sag. Stiffer motor mounts really help. Many times these frames have sagged slightly over the years which changes motor location ever so slightly along with accident damage, general abuse, aftermarket parts that aren't exactly stock in dimension and don't even get me started on Big Block vs small block motor mounts and stands on early Chevy's.
If everything is as "correct" as it can be and urethane mounts don't cure it, a slight "clearancing" of the offending pipe will not affect power and will rid it of the annoying noise.
Hope this helps

[DynoDon]

For Pontiacs, Dougs are universally considered to be the best fitting. Now, to be completely honest I'm not very favorable to the "factory" ceramic that Dougs/Pertronix does. I personally returned a set of coated Dougs and replaced them with a set of Dougs that were coated elsewhere. That being said, I know I'm picky.
.
We use the highest regarded Ceramic Coater in So Cal and as a general rule do not have coating issues. But having said that we/they aren't perfect and occasionally there have been some issues, Especially when they get very busy. We do get compliments on our coating regularly, but some times one slips through. Sorry you had a problem.

[AM.MSCL]

don't even get me started on Big Block vs small block motor mounts

Now you have me really wondering about something!
The car was originally a 350 motor that someone dropped in a 400 form a 70's auto car. Are the motor mounts for these 2 motors different?
Thanks
Ray

[DynoDon]

67-69 Firebirds had a unique motor mount - both the chassis AND the block mounting pattern. Normally the later motors are drilled with the pattern to fit the early cars, but if someone mixed and matched the mounts that could be a source of the problem. My Pontiac source also tells me that there is a bit of slop in the system that man times causes clearance issues. He suggests loosening the motor mounts at the frame and between the stand and rubber mount and trying to shift the motor slightly away from the steering box. Doesn't take much to make a difference.

[AM.MSCL]

67-69 Firebirds had a unique motor mount - both the chassis AND the block mounting pattern. Normally the later motors are drilled with the pattern to fit the early cars, but if someone mixed and matched the mounts that could be a source of the problem. My Pontiac source also tells me that there is a bit of slop in the system that man times causes clearance issues. He suggests loosening the motor mounts at the frame and between the stand and rubber mount and trying to shift the motor slightly away from the steering box. Doesn't take much to make a difference.

thanks
Ray

[wmhjr]

I'm not as familiar with the gen1 birds, but here's another option. You could swap out the rubber/poly mounts for solid motor mounts. Butler Performance has them and they're pretty inexpensive. So long as you're making just a slight adjustment, you can dial the position right in. I'm using solid mounts with a far more aggressive motor and a solid u-joint rather than a rag joint in my steering, and it is very acceptable. Plus, no worries about destroying a motor mount (which I have done)

[wmhjr]

We use the highest regarded Ceramic Coater in So Cal and as a general rule do not have coating issues. But having said that we/they aren't perfect and occasionally there have been some issues, Especially when they get very busy. We do get compliments on our coating regularly, but some times one slips through. Sorry you had a problem.

Don, no problem. Like I said, I know I can be picky. I love the quality of your headers but as I said I was just not too impressed with the ceramic. I've got pics of them if you're interested, but brand new in the box there were some large portions that were not polished and areas without coating were too large. Plus, there was rust in the weld areas around the flanges. I'd say that functionally they were fine, but not to my expectations. For a "Driver" the only thing that bothered me was the rust. I just needed more, so I paid extra for it. No problem - Thermal Tech sells your headers but coats them and I ended up with the best of both worlds.

Like I said, let me know and I can easily spot you some pics of the headers - I'm pretty sure I retained them even though the headers themselves were returned. I know you folks got the pics before but maybe not you personally.