[takid455]

Originally Posted by KEN CROCIE

I have a set of H-O tri-y s in the garage. would you like to borrow them for your project?

Ken,
I may take you up on that offer. I have a modified HO tri Y set in the attic. Need to see what all was changed.

Sent from my SM-S901U using Tapatalk

[KEN CROCIE]

The D port try y fit only the gen 2 F body. The round port try y fit A& F body

[Half-Inch Stud]

Originally Posted by takid455

Ken,
I may take you up on that offer. I have a modified HO tri Y set in the attic. Need to see what all was changed.

Could be a decent rotation of ownerships. Is your modified set rusty, or can pipe cuts be clean enough to be prepped for welding?

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Pulled the RH 4-tube Header, so here it the "BEFORE" image. Idea is to make it a 2-tube Header. Pri dia is big enough.

Probably keep the Collector scheme as-is with this ised Header. A 304 stainless "kit" would be a 2-tube header with a very different Collector scheme: 6-8 tube crossing over in front of the trans Pan to LH Collector.

[tom s]

How important to correctly clock a tri y header?Tom

[R 70 Judge]

Originally Posted by takid455

Ken,
I may take you up on that offer. I have a modified HO tri Y set in the attic. Need to see what all was changed.

Sent from my SM-S901U using Tapatalk

Originally Posted by KEN CROCIE

The D port try y fit only the gen 2 F body. The round port try y fit A& F body

I have a used set of the HO Specialties Tri-Y round port headers in storage. They came off of my brothers 72 TA 455HO 4 speed which is in pieces in the garage. I haven’t seen them in years but I think they are in decent shape.

[Half-Inch Stud]

Originally Posted by tom s

How important to correctly clock a tri y header?Tom

Clock must mean "time" such as pulse time. Well since the 4-tube is rudely unclocked for pulse reflections into vulnerable CYLs. Then clocking the 2:1 Header becomes stupid easy on the Primaries, yet painful on the Collector. Tri-Y assumes a 3rd Y. I see the 3rd Y as a pulse interference problem which a divided Collector or crossover mitigates:

2+4 needs isolation from 6+8. likewise 1+5 needs isolation from 3+7.
The most excellent isolating Collector scheme appears to me as 6+8 crossing over to the LH Collector. Whereas the 3+7 crosses over to the RH Collector. Equal lengths become impossible but may-never-have-been of any value with 4:1 Collectors.

Timing becomes a compromise in exact reflection timing for all CYLs, a subtlety actually for a spread clocking across 3000-4000 rpm. Below 3000 rpm is EGR, at least without offensive Reversion. Above 3500 rpm is a refection time for BOOST that should improve Torque over the 4-tube up to some rpm, that which the 4-tube ought dominate as is the tradition.

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Primaries are 1 3/4" ID, about 1.875" OD. You can see the inefficiencies in the 2 remaining Primary tubes: acute bends get hot.

2 will go direct into 4. 6 directly into 8. This mock will get the GTO running, and serve ad a templte for New Stainless: would be more efficient Primary tube with obtuse bends, and the crossover ability ( in front of the trans pan will work ).

48s D-Port for jig is sufficient. Outer bolts are the only same position as O-Ports.

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2-4 done. Working the 6-8, then cap the Collector. My welding stinks (15 year old spool?)

[b-man]

Some first-gen Firebird Tri-Y headers I built from some used GTO 4-tube D-port headers:

https://forums.maxperformanceinc.com...d.php?t=598736

I did clock the tubes to match the round-port H-O Racing Tri-Ys I had at the time.

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Your welds look pretty good! Your Driver 1-5 looked like a painful task. Overall you got it done!

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The Collector Cap is formed. Gonna need real good luck welding that on. The 6-8 pipe is a tough fit. Need a fortunate dent to provide Header bolt access.

[tom s]

For awhile Tyree build Tri Ys.Hated the sound uncapped,he went back to 4 tubes.Tom

[punkin]

I'm on board with this as well 2" primaries and fitment under the car would push me into taking a long look at something like this.

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Yesterday: Shaped the metal Cap, removed the #6 bend too ( probably shouldn't have done that. #6 pipe to #8 needs 2-bends to get right and the fit pip only has 1-bend. Roufhed-in hole into #8. Today: Welded Cap on.

Geez, would have been nice to start with a core that had these 2 Primaries on the Collector's upper portion, but no they are on the lower. Headers like these, along with the Dual-Plane Manifold ought to have a very low reversion, along with uniform CYL inhale fill. Eager to get-er-done.

[takid455]

Gathered a bunch of notes. From a business perspective, order of headers would look like this:

1 st batch - 70-81 F body D port 1 7/8
2nd batch once 1st batch takes off - 70 - 81 Fbody O port 1 7/8 or 2"

180 degree, 3.5" collectors, 2" D ports , 1 offs , ect are neat & cool, but not feasible on the business end of things. Also, At the larger tube sizes, you'll want a 4 tube or zoomies at those power levels if said engine truly requires such.

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Finished the RH 2-1 Header. Center Flange will likely need double-gasket. Goal was to get it done.

Install should go easy, when it comes to headers, maybe like a Manifold. Hope to drive it soon, and decide on the SS 304 version.

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This effort is independent of the "Tri-Y Fbody 304 SS" opportunity. Yet i can hope some idea can drift-out, and cause a common fab for A-body, F-body. Heck G-body too.

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Installed, and not done until that last friggin Header bolt gets threaded. 5/6 aint bad, but 6/6 would be done. Will shoot & post the topside photo when the last bolt threads-in.

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Should be last photo-post on the RH side modification of a 4-Tube to 2-Tube Header.
Pro-tip; notice the use of a 5/16 thru-bolt and nut for simplified #6 Blind Header bolt install.
3/8 from below is a two-hand deal, and wasn't catching.