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Tri-y style headers tend to be optimal up to 5,500 RPM, so a good choice on most SBC's.
The 5,500 RPM thing is true for the off-the-shelf TRI-Y's available for our old SBCs, but not true for Tri-Y's generically.
Calvin Elston is one of the "Kings of Header Design" (along with the folks @ Burns Stainless) and designed and made the headers for many winning Nascar teams, and he maintains that properly designed TRI-Ys can produce more torque and more HP than 4:1 collectors up to 8,500 RPM (and no professional engine builders dispute it when he says it). The problem is that as you go up in RPM and cubic inches the IDs have to get bigger and the lengths of each section have to get shorter and at about 8,500RPM, it's just not physically possible to manufacture a TRI-Y any more.
I know the subject of Tri-Y vs. 4:1 is near a "holy war", but TRI-Ys have no 5,500 RPM limitation if you're getting a custom header built. (The Stans and Doug's / Thorley's headers ARE designed for about a 5,500 RPM peak, though and they're the only off-the-shelf options other than Shoenfelds, which I don't think will fit on a C3 and they START at 1 3/4 or 1 7/8...)
Adam
-I also think Calvin's statement is comparing TRI-Y's to traditional 4:1 colletors and not "proper", modern Merge collectors ALA Burns Stainless.
Last edited by NewbVetteGuy; 04-25-2019 at 06:09 PM.
I haven't gotten to the engine work on my '80 yet, but this type is what I'm looking to get. In my search, Stans Headers looked like a good choice. I spoke with them and they are quite knowledgeable.You can search the forum for posts form people who have used them.
Stans are here in the Seattle area so their labor is very expensive. I know they've had a hard time finding and keeping people as I see their "header fabricator / welder" job listings repeatedly pop-up, so that slightly concerns me, especially as I have the stupid raise D-port Profiler heads with the bolt holes in the wrong spot so I need a custom flange, AND I want O2 bungs welded in, AND I want stainless... (They're AWESOME for off-the-shelf stuff, if you can afford it, but I need customization and their labor rates are high; not their fault, but they're HIGH.)
(I wish I had a custom header shop local who would work with Burns Stainless; if you buy their fancy merge collectors, they have a custom header modeling system and they'll design you a complete custom header system or complete exhaust system that's ideal for your engine and usage and they can put all the components together into a single order and just ship it to you / your fabricator....) I don't trust any random Craigslist "stainless" welder to make a header and not screw it up; had some BAD experiences with a supposed "stainless welder" when I built my stainless home brewery... Never again. -If I had stainless welding skills- like proper ones and the patience, I would have Burns build a modeled "ideal" custom header and ship the parts and weld it up.
Adam
Last edited by NewbVetteGuy; 04-25-2019 at 06:08 PM.
Look under Chevrolet Headers, NOT, Corvette Headers.
You won't find a better header for your car, for ANY price!
Steve, I just went over to their site. They have side-exit headers and then standard rear-exist exhaust headers for C3s, but they have 2" primaries and 4" diameter collectors...
Do they have any "standard" headers for C3s with the typical <450 hp? (like 1 5/8" or 1 3/4" primaries).
KOOKS..... had many different headers and brands over time,,,I would bet 20 over all the cars we have built over the years.. I would say 4 sets alone for the C3.
1st was changed out due to not sealing correctly.. thinner flange,
2nd was changed out on a 383 upgrade due to not tuned... less hp
3rd was changed out to go to a all out 427 build .... pipe to small
4th and in ... AMAZING header in every way..... fit, finish, fit in engine bay, build,,, and on the dyno,,,KOOKS 1 7/8" Ceramic coated... made in USA
Wow... I've never seen those before. Pick your primary and collector size, 304 stainless and PROPER Merge Collectors with scavenger spikes?!? The 1 5/8" primary versions have 2 1/2" diameter collectors. They include O2 bungs welded in!
They're not cheap, but that's a GREAT feature set and the 1 5/8" + 2 1/2" collectors are just perfect for the typical 300- 425hp range SBCs... (By that I mean lots of exhaust VELOCITY to keep torque up and still plenty of FLOW for 425hp.)
Adam
Last edited by NewbVetteGuy; 04-25-2019 at 07:54 PM.
ARH are the only headers we use on all our C5-7 race and track cars.
I think these are going to be cheaper than my quote from Stans for Stainless Tri-ys with the flange made to work with my Profiler D-ports, and O2 bungs added...
I just don't know how they'll fit with my stupid Profiler D-ports and I'm afraid if I slot the bolt holes, they'll just vibrate their way back down again if something doesn't get at least tack welded back into the top of the now-elongated bolt holes...
They're a really great option. Thanks for sharing.
I think these are going to be cheaper than my quote from Stans for Stainless Tri-ys with the flange made to work with my Profiler D-ports, and O2 bungs added...
I just don't know how they'll fit with my stupid Profiler D-ports and I'm afraid if I slot the bolt holes, they'll just vibrate their way back down again if something doesn't get at least tack welded back into the top of the now-elongated bolt holes...
They're a really great option. Thanks for sharing.
Adam
I have hooker super comps on my 79 with fastburn heads which also have the D port and have no issues
I have Doug's headers in my 355 and they fit absolutely perfect. The collectors are tucked close to the front of the floorboards, so you need to have a shop bend or weld some decent extensions, but that provides great ground clearance. They aren't cheap, but best headers I've ever installed out of the box. Mine are 1-5/8 and you'll want 1-3/4 with your cubes, but check them out.
I have hooker super comps on my 79 with fastburn heads which also have the D port and have no issues
I think D-ports are WONDERFUL. Anti-reversion is just magic "free" average power, and MPG ala low-end torque for a perf build. The problems with the Profiler exhaust ports and header fitament aren't that they have D-ports, it's that the D-ports are pretty significantly raised AND they didn't center the bolt holes on the port -they kept them in the stock location. -The fastest and most "important" air in the exhaust flow is at the top of the port and without raising the location of the bolt holes almost ALL standard headers (of appropriate size) and almost ALL standard gaskets cover the top of the port (there's one gasket that's known to work without having to trim it). The Profiler exhaust ports also aren't even all the exact same size (the outer ones are different than the inner ones).
The FLOW on the Profiler exhaust ports is AWESOME, many pro engine builders, head porters, and head designers think that at actual exhaust flow pressures and temperatures they're probably better than the AFR exhaust ports; they focused on performance at the cost of fitment. (Probably the right trade-off for the typical Reher Morrison Racing customer, but maybe not the typical $1,000-$1,500 SBC head customer... and it would've been SOO easy to just move the dang bolt holes; moving the bolt holes would've made more room for spark plug clearances, too; I really don't understand why Profiler never "Fixed" this.)
It's not a HUGE issue, but it does mean that I can't just bolt on a set of headers.
-I just wanted to clarify that others with D-Port exhausts don't need to necessarily worry about it as much, but if you bought the Profiler heads or the Jegs-branded Profiler head, you need to make sure they fit up correctly and probably elongate the header bolt holes and then figure out how to ensure the header doesn't slowly fall back down... (ATK engines sells a custom Profiler casting that has "normal" exhaust ports -you lose some flow, but you can just add a few more degrees on your cam's exhaust duration to make up for it.)
Adam
Last edited by NewbVetteGuy; 04-26-2019 at 12:30 PM.
What is the "best" type of flange to use? How much better at sealing are the "ball" -type flanges vs just the flat flange with 3 bolts?
Is the cost premium of the ball-type flanges "worth it"?
WILL do!
-I actually already created a paper rubbing of my exhaust ports and bolt holes for seeing how I'd need to modify my current headers (which will DEFINITELY be used to break in the motor), and MAYBE, just MAYBE they'll let me mail it to them to have the bolt holes put in the correct place... (I did this for Ken @ First Fuel Injection to show him how my intake ports didn't 100% match the custom gasket for his intake (they come with a Felpro 1204-sized port stock and then Ken has a CNC machine with programs to increase them to a 1205 or a 1206 -the Profilers intake ports appear to be a SLIGHTLY raised version of a 1206, so I took a paper / crayon rubbing and mailed it to Ken and then he perfectly port matched the intake before sending it to me. I was a pretty happy camper and SUPER glad I asked him to mail me a gasket before the intake. Yea, I get that it's probably like a 2 or 3 CFM difference but that's a 4-6 HP gain for "Free".)
Adam
Last edited by NewbVetteGuy; 04-26-2019 at 12:43 PM.
What is the "best" type of flange to use? How much better at sealing are the "ball" -type flanges vs just the flat flange with 3 bolts? Is the cost premium of the ball-type flanges "worth it"?
Adam
YES!! less leaking, and gives you a bit of leeway as far as alignment is concerned, ie.. you can go a little left right up or down and still have a great seal.
The 5,500 RPM thing is true for the off-the-shelf TRI-Y's available for our old SBCs, but not true for Tri-Y's generically.
Calvin Elston is one of the "Kings of Header Design" (along with the folks @ Burns Stainless) and designed and made the headers for many winning Nascar teams, and he maintains that properly designed TRI-Ys can produce more torque and more HP than 4:1 collectors up to 8,500 RPM (and no professional engine builders dispute it when he says it). The problem is that as you go up in RPM and cubic inches the IDs have to get bigger and the lengths of each section have to get shorter and at about 8,500RPM, it's just not physically possible to manufacture a TRI-Y any more.
I know the subject of Tri-Y vs. 4:1 is near a "holy war", but TRI-Ys have no 5,500 RPM limitation if you're getting a custom header built. (The Stans and Doug's / Thorley's headers ARE designed for about a 5,500 RPM peak, though and they're the only off-the-shelf options other than Shoenfelds, which I don't think will fit on a C3 and they START at 1 3/4 or 1 7/8...)
Adam
-I also think Calvin's statement is comparing TRI-Y's to traditional 4:1 colletors and not "proper", modern Merge collectors ALA Burns Stainless.
Calvin also said unless your having custom headers made to your specific application to just buy whatever out of the box 4:1’s....
04-25-2019, 05:59 PM
