Ok so I was wondering who makes the original tri y headers? Dougs headers or Doug thorolley?
Also I’m planning to do an AOD swap and want to run tri-ys. Which versions work? And will they work without the aod? Lol
The cat in question is a 67 with a 302 in it.
I used the chrome Scott Drake version on the '67 w/a toploader. I needed to modify the clutch linkage some.
I’ve used the ones from Tony Branda on several 67 - 68 Cougars with 289 / 302 / 351. They are exact copies of the originals that were installed by Shelby back in the day, and sold for the Cougar / Mustang by Ford and Mercury dealers. Click here:
You are not going to have any problem with clearing the AOD, but you will have to use the PS ram drop bracket if you intend to use factory style power steering.
Interesting. I’m not going to be using conventional power steering so I think I’ll be good there.
To each their own but Tri-Y’s will never flow as well as full length, four-tube headers.
Yeah but tri-ys are for down low torque. That’s what I’m looking for
Are they? I would be interested to read about how a more restrictive header improves low end torque.
1969xr7vert, a more “restrictive” exhaust tends to give better torque where as a slightly big exhaust will sacrifice a little torque to make more hp higher in the rpm. running a stroker Cleveland I’m sure you are willing to give up a couple ft lbs to gain the extra hp. personally I like full length headers because I figure I’ll never be able to stop making things faster so may as well go all the way right off the bat.
Royce - do they need any modifications to fit 67 / 68
I’ve bought a set for the 289 in my '68 on the advice the only clearance mod required is the drop bracket for the OEM power steering ram. Time will tell if that matches up with reality…
I like the idea of tri-ys because of their low down torque characteristics and they don’t hang as low as typical long tube headers. Plus they’re available locally in stainless steel at a very good price.
I’ve only used them on 67 - 68. No mods of any kind, excellent fit with either 289, 302, or 351W with C4 or FMX or 4 speed or 3 speed…
Actually the 4 into 1 headers give better torque and horsepower, but the difference is minimal, particularly so if you have mufflers. So I have to agree with Bob, he’s right.
There may not be much difference until you have an engine making 400 horsepower and above. I know that several of the 5.0 Mustang magazines have had dyno tests comparing shorty tri - y headers with 4 into 1 long tubes and the difference in performance was on the order of 2 percentage points.
I wouldn’t say you have to Royce, it might spoil a long standing tradition! 
But, just the same, thanks for saying so!
Sorry, meant to reply w/ quote and accidentally reported.
I am with you on this one. The idea of a full length tuned header is that it improves torque everywhere (which is why so many RV owners use them on top of a slight mpg increase). Full length tubes made a huge difference everywhere on my 289, like an extra gear’s worth of tire spin in D. I would never be convinced to use anything but full length if not using manifolds.
I have long tubes on my car, and personally like them best, but if we are talking 2 percentage points difference at most and tri y’s fit better, (hookers needed a little modifying for me) I don’t see any reason to go long tube. Unless you’re building something a bit stronger than I thought
Although I’ve never used tri-ys, I prefer the long tubes on my car, and aside from the steering ram bracket, had no fitment issues. I will say that they made the biggest difference on cars with more cam, more compression, etc., but still woke up my 289 (Comp 275 Dual Energy, Dual plane, 600 dual feed Summit, but did have 2100 until two weeks ago) pretty nicely, and did help with upper end breathing even with the milder cam and 2 barrel. 2% on a dyno could be a change in atmosphere, so on a very mild engine, who knows. Still, I won’t be losing any sleep over my choice. Especially considering I always end up a little more radical as time wears on (funny how you catch up to your engine and all of a sudden you think the car is slower).
I say, if you prefer them and the install would be easier yet, the tri-ys might be a better choice for you.
For what it’s worth, there’s a lot more to headers than just ‘how much does it flow’. The timing on exhaust pulses creates a scavenging effect at certain RPMs, literally ‘sucking’ the exhaust out of the chamber when you hit a certain range in the powerband. The distance each exhaust pulse has to travel before it hits a junction changes the harmonics, and determines at what RPM that effect will happen with a given engine. With a long-tube equal-length header setup, there is one BIG harmonic that happens right at the first collector. So, that ‘sweet spot’ happens mostly just once in the usable RPM range, fairly high up. That means you get a strong surge on the top end, where the header works best.
Tri-Y headers usually have TWO harmonics that they will hit as your engine revs, because of how they merge once a short distance from the head, and then lower at the collector. Neither is as strong as the single ‘sweet spot’ of the equal-length long-tubes, but that means that you get a nice boost down low, and then again up higher in the RPM band, spreading out the scavenging effect over a broader range, but not as intense. They start to lose steam around 55-5800 RPMs, whereas the long-tubes are really only starting to kick in hard after about 5k, typically. On a street motor that’s all done by 5200, the long-tube headers never get to do their magic. With more mods, and higher RPMs, they start to come into their own.
Generally, ANY header will work a lot better than the old restrictive log manifolds, for performance. Tri-Y headers offer easy fitment, great street performance, and the fact that Carrol Shelby used 'em on his rides should say a lot about why they are a good choice.
If you just want top end, and enjoy racing, the long-tubes shine. And let’s face it, compared to those old cast iron manifolds, you’re going to get a boost throughout the RPM range, not just at the top. The factory manifolds may be quiet, and sealing is a non-issue with the thick metal flanges, but those old doorstops were never meant for performance. They suck at ANY RPM range, and will probably cost you at least 10-15 horsepower over anything else.
The main thing to consider is how your exhaust will work with your particular engine, though. If you go too big with headers, the flow will be sluggish coming down the pipe, and scavenging, if it happens at all, will be weak, due to the lack of strong pulses in the exhaust system. If you go too small, then you get a restriction, and gas can’t get out of the cylinder effectively. Best check with a pro to find out what they’d recommend for your particular engine setup. For a typical stock or even hopped up small block Ford, the Tri-Y setup with 1 1/2" primaries are pretty hard to beat on a street-driven car. They may even improve your mileage. (I gained about 2 MPG with mine, compared to the factory logs)
Excellent post! Couldn’t agree more - so often the mentality of ‘bigger/longer is better’ prevails without any proper analysis.
Too many cars that spend all their life on the street are fitted with racing parts that provide little benefit away from the track/drag strip.
Which ones did you get- the Castle Headers? I need some for the 68 as I’ve just cracked the LHS exhaust manifold
I’ve only used the ones from Tony Branda. Click here: