Best fitting headers - 67 GT350 four speed manual steering

[Horsman]

What do you guys recommend for the best fitting headers that do not require modifications?

[shelbydoug]

What do you guys recommend for the best fitting headers that do not require modifications?

I doubt that there is any such thing. They all are going to need some kind of mod to get them right.

I like the JBA 6611. They fit will little trauma.

[greekz]

I have a set of reproduction Tri-Y headers on my GT-350.  I have an auto and power steering, but not sure if it makes much of a difference.  The headers fit with no problems or modifications, I just had an H-pipe made at the muffler shop.

Greek

[Sixx7shelby]

I have Hooker competition headers on my 67 4speed 350, still have power steering. No modification to headers at all, just had to install lowering bracket for power steering slave cylinder.

[Bob Gaines]

I have Hooker competition headers on my 67 4speed 350, still have power steering. No modification to headers at all, just had to install lowering bracket for power steering slave cylinder.

Keep a eye on the lowering bracket. The longer bracket gives extra leverage to cause flex to the base. The flex will often cause the captive nuts in the frame to loosen. If the bracket moves when turning at all then it is happening. Welding to the frame rail is the best alternative however even that will some break loose. It is more of a problem on the heavier BB but happens to some SB also. If it is not moving feel lucky and keep watch. 

[GT350DAVE]

I have used both hooker headers and the Tri-Y's. Both needed some adjustments. I like the sound of the Hookers but the heat generated by them was a major problem. The Tri-Y's fit easier but didn't have the sound over the stock manifolds but prefer the Tri-Y's. Ground clearance definitely improved and the floor temperature for longer trips was greatly reduced.
Dave

[Bossbill]

I've got the huge -- humongous tube -- JBA headers on the Boss. What a pain in the butt. I do so hate those things. I'm tired of them regrading my driveway because they hang so low. Ok, the car is lowered too...
Next time the engine is out it goes back to stock. 

Although I've never tried these specific headers the thought of shorty 5.0 Fox style headers have always been at the back of my mind. And:
https://www.cjponyparts.com/scott-drake-shorty-header-1-5-8-black-painted-pair-289-302-1965-1970/p/EXHD78/

Just the ability to retain your standard power steering bracket (if I read this right) is worth the few horses you lose with a shorty vs the full length.

Now if you think they fit without messing about:
"1967-1970 Mustangs with a manual transmission will need to have the clutch equalizer bar modified."

I like the idea and would probably just contract this out with someone who builds headers and can route the tubes around the equalizer bar correctly. We have Stan's Headers nearby to do that.

I laughed a bit when people complained about the paint flaking off. Ya think?

[Bob Gaines]

I've got the huge -- humongous tube -- JBA headers on the Boss. What a pain in the butt. I do so hate those things. I'm tired of them regrading my driveway because they hang so low. Ok, the car is lowered too...
Next time the engine is out it goes back to stock. 

Although I've never tried these specific headers the thought of shorty 5.0 Fox style headers have always been at the back of my mind. And:
https://www.cjponyparts.com/scott-drake-shorty-header-1-5-8-black-painted-pair-289-302-1965-1970/p/EXHD78/

Just the ability to retain your standard power steering bracket (if I read this right) is worth the few horses you lose with a shorty vs the full length.

Now if you think they fit without messing about:
"1967-1970 Mustangs with a manual transmission will need to have the clutch equalizer bar modified."

I like the idea and would probably just contract this out with someone who builds headers and can route the tubes around the equalizer bar correctly. We have Stan's Headers nearby to do that.

I laughed a bit when people complained about the paint flaking off. Ya think?

Keep in mind that the 67/68 hipo equalizer bar may have to have the bar modified or not fit well with headers however a stock 289 Mustang Z bar may not. . For instance a stock non hipo Z bar fits much better on 65/66 GT350 and tri Y headers then the hipo Z bar. That is probably why so many of them got changed over the years.

[Sixx7shelby]

I have Hooker competition headers on my 67 4speed 350, still have power steering. No modification to headers at all, just had to install lowering bracket for power steering slave cylinder.

Keep a eye on the lowering bracket. The longer bracket gives extra leverage to cause flex to the base. The flex will often cause the captive nuts in the frame to loosen. If the bracket moves when turning at all then it is happening. Welding to the frame rail is the best alternative however even that will some break loose. It is more of a problem on the heavier BB but happens to some SB also. If it is not moving feel lucky and keep watch.

+1

Already had it happen years ago Bob, thanks for posting as I did not include that in my post.

[Horsman]

Great information guys, thank you!

My car did have headers installed when I pulled the engine, I guess that explains why my Zbar looked slightly modified. The header brand was unknown and they looked horrible since the car had been sitting for 40 plus years; the headers went in the trash. My engine builder said the HiPo manifolds will choke my engines performance so I was considering getting some headers. Still on the fence, I guess I can run the manifolds first and see how it performs. I agree, headers are usually a pain.

[shelbydoug]

As I mentioned, I am running the JBA 6611 headers on my 68GT350. I had the Hookers on there and the ground clearance was too low.

The collectors on the Hookers point down and start at a lower reference point then the JBA's do to begin with.

The Hookers are 1-1/2 primary tubes and the JBA's are 1-3/4. The JBA's will fit without the ps extension but the rubber accordion boot will be up against the #5 tube.


With manual steering there is no issue with steering components at all with either the Hooker or the JBA headers.


The difference in the size of the tube diameter is worth 1/10 in the quarter mile which rough translates to 75-80hp gain over the Hookers.

The location of the collectors and the angle of them on the JBA's is MUCH better then the Hookers. They are tucked up into the chassis and will not have any ground contact issues themselves whereas the Hookers will.

My car has a lowered suspension and with the Hookers, you could not make a fist and slide it under the collectors.


It's irrelevant what will fit on a 65-66, or a 69-70. They are SIMILAR chassis but vary enough to not be an exact comparison of details, as well as how a Boss 302's or a FE fits from the same manufacturer. What matters is what fits with a 289-302 in a 67-8 chassis. Both will fit. The Jba's fit much better, even with the bigger tube.


IF you are running stock displacement, heads, cam and induction, the bigger tubes won't do anything for you.

I have run hp iron manifolds also. In fact I even tried iron 351w 4v manifolds which are larger in diameter then the 289hp manifolds and have the same configuration. They are a waste of time. They are giving away at least 30hp and make the engine feel small and rinky-dink.


Tri-y's are not what you want to run on these cars. They were a compromise on the 65-6's and were put on there for easier installation as much as anything back in the day. They are not much better then the iron manifolds are and give away almost as much potential and power.

That's pretty much what I know about the subject. *subject to revision.

[Horsman]

My build is a 331, bigger roller flat tappet cam, and bigger valves, pump gas friendly compression. I do not plan on racing the car, just having fun on the street. 

[shelbydoug]

My build is a 331, bigger roller flat tappet cam, and bigger valves, pump gas friendly compression. I do not plan on racing the car, just having fun on the street.

Mine is a 347 with AFR 185 heads and 2x4 Holley's on a Ford T/A intake. 550 lift solid cam. Just under 10:1 cr. The bigger tubes work better for me.

You don't need to race the car to understand 1/10 better in the 1/4. It is a basis for comparison like head flow is.

[greekz]

I was unaware of the equalizer bar and lowering bracket issues.   Learn something new every day!

[Horsman]

My build is a 331, bigger roller flat tappet cam, and bigger valves, pump gas friendly compression. I do not plan on racing the car, just having fun on the street.

Mine is a 347 with AFR 185 heads and 2x4 Holley's. The bigger tubes work better for me.

You don't need to race the car to understand 1/10 better in the 1/4. It is a basis for comparison like head flow is.

The headers are a consideration, especially since it will be much easier to install a set since the engine is out of the car.