Header Question

[65stangCT]

I am installing a 331 stroker with 400HP, and a 2.5 magnaflow exhaust. I am looking to use Thorley Headers. The car is a 65 Coupe for street use.

My question is Long tube or Tri Y, and what are the plus/minuses of each.
Thanks

 

[LMan]

Since Im guessing you have aftermarket heads, I recommend longtubes if you can make them fit with your steering.

 

[The Dan]

Though I don't know all the pro & cons, ask yourself this...how many pro-stock cars have you ever seen with Tri y's? Since those guys look for every competitive edge they can get I would say that there has to be some legit reason they choose long tubes over tri y's. However, I think Tri-y's are more suited for the street and develop there power down low, where as the long tubes will breath better up top. If your only going to run on the streets I would lean towards the tri-y's since you'll be spending most of your time in the lower power band going light to light. Though I do like the sound of my long tubes. Very throaty.

 

[65stangCT]

Thanks guys. I spoke with a representative from Doug Thorley and they reccommended the Tri Y. Basically the TriY gives better low/mid range torque, and the Long tube doesnt start to produce until after 5000rpm.

 

[LMan]

Hmmm, I see that with a 289, but you are answering the torque question with the stroker.......I don't see the >5000-RPM argument at all. They must mean that LTs outshine Tri-Ys >5k, at least that is my guess.

...but I've been wrong before, I'm no header expert. But I would still select LTs over TriYs for a stroker.

 

[rbohm]

for the street, i say tri-y's as they make better mid range torque that the 4-1's(both are technically long tube headers). i would however recommend that you get tri-y's with a 1 5/8" primary tube, as the 1 1/2" tubes that shelby used are going to be a bit smalle for your motor. and yes, the 4-1's have a power advantage above 5k rpm, though it really isnt very big.

 

[SoCalCruising]

You know, Doug Thorley doesn't own that comapny anymore. He now has Doug's Headers in Anaheim, CA. His current designs are superior to the old stuff sold at Thorley Headers. The old stuff is 1 5/8 primary, into 1 7/8 secondary, into 2 1/2 collector. The new stuff is 1 5/8, into 2" into 2 1/2, with better transitions. Fit is great - I have Doug's on my '66.

As for Tri-Y applications, they are the preferred header for many high-end NASCAR applications, given that they look a lot different than what we can get. The NASCAR primary tubes, especially, are longer and tuned for max. scavenging. The secondary tubes are also longer. As for street applications, I have seen several dyno runs where Tri-Ys give up a little down low, compared to long tubes, but have superior mid-range, and aften better high-end power. Fit is generally better on our cars and, since you will be having traction problems anyway, you should be happy to give up something down low (where you can't use it) for more mid-range (where you can use it).

Ummm, people often say that long tubes make better top end. The question is: compared to what? Compared to stock manifolds - YES. But, when just comparing tubular headers: long tubes are good through mid-range RPMs; Tri-Ys not quite as good at low RPMs, but better at mid-range RPMs; and shorties give up low and mid-range power for top end. That all assumes comparable tube sizes. Enlarge the tubes and we're not apples to apples anymore. Make sense?

Hope that helps.