Header Flanges for 223cid

[texas_rat_trap]

Hey guys,
Just picked up these Header Flanges from Erape...I mean Ebay and was wondering if anybody recognized the part # or where they may have come from. Also does anyone know how the heat riser on the intake works with a header? Do I need to weld some sort of heat riser on the header and what would be the best way to custom weld headers on the flanges, I was thinking of buying one of those build your own header kits from Jegs or Summit. Oh one more question, I wonder why its split 2-4 and not a one piece flange.

Part# or Tag#----F5331K--- fits (215-223-226)

 

[godheadcustoms]

Not really any help on this, but I'm curious about the flanges. Were they a one-time thing, or from a speed shop (or whatever) that has a few of them lying around? I'm guessing they were a once only gig, but it would save me some fab time to buy a set of flanges. Also, what the dia. of the pipes?

 

[godheadcustoms]

There could be a couple of reasons for the 4-2 split. 1. possibly it was one piece and it broke at some point, so someone rounded it off to look better. 2. because of thermal expansion you really don't want one long flange. It can cause the outer ports to leak due to the stacking effect of thermal expansion. Thats why you'll often see header flanges with slits cut between the ports to allow the headers "room to grow". Although you would think they would have split them into three, not two...3. depending on how old they are, early header science didn't really seem to embrace pulse tuning (or even know about it, for that matter) for a scavenging effect. They usually designed them to only sound better/different or to look like they flowed better without regard to the science behind the "why". Think of the split log exhaust manifolds, they were often spilt 4-2 because it was easier to cut and weld them that way. But, while the car SOUNDED faster, they were in fact probably making the same or less horsepower due to screwing up the exhaust pulses.

As far as intake heat, it all really depends on where you live. It's not absolutely necessary in the warmer winter climates, but probably is anyplace that gets an actual winter. You can do a water heated intake or use an exhaust heated one (ie.-a stove pipe), both will have the same effect. The exhaust heated one can just be a small pipe welded to the outside of one of the primaries and connected to the bottom of the intake. Water heat might be easier and cleaner looking. Honestly, I've never bothered with intake heat, but I live where it seldom goes below 45-50* in the winter. In fact, I usually disconnect any factory heated intake to try and get a little cooler charge going in.

 

[rmt]

I believe the main reason for a 4/2 split dual exhaust system compared to a 3-3 dual exhaust was for the sound effect only. That's all I've ever heard. The idea goes waaay back.

 

[texas_rat_trap]

Not really any help on this, but I'm curious about the flanges. Were they a one-time thing, or from a speed shop (or whatever) that has a few of them lying around? I'm guessing they were a once only gig, but it would save me some fab time to buy a set of flanges. Also, what the dia. of the pipes?

They look to me to be one off header flanges, but I thought it was wierd that they had a part #, I was just tryin' to figure out if they were truck headers at one time & they cut them off so they could sell them for both applications, since truck headers will not work in car applicat. I haven't recieved them from the seller yet, so not sure on dia. of pipe's. The seller said they have never been installed so I know the flange did not break into 2 pieces. As far as the split...I guess I could still fab a 3-3 split header for a more even flow in which will probably sound bad ass either way...I mean sh!t ...it sounded bad ass when I fired it up with 2 2bbl.'s & the single outlet exhaust manifold...you can really hear the cam heavy lope. Highly recommend Schneider Cams did a great job. Cant beat the price either $100.00 for custom grind cam.

 

[texas_rat_trap]

Don't know if any of you guy's remember that experimental 3-3 split exhaust manifold I was workin' on...well, if these headers work out okay I may sell the manifold cheap...I mean like what I paid for the exhaust manifold maybe a little more, but here are some pic's of the unfinished manifold still need to weld on the other flange and the heat riser valve is broken. But hotrods don't have heat risers anyways, lol.

Don't know how well its gonna work...but it is what it is. See what LoneStar Beer & too much time in the garage does to a man!

 

[godheadcustoms]

If it were me, no matter where the flanges are spilt, I would definetly run two collectors split 3-3. I think I would also look at cutting the other side of the flange to match, partly for looks but mainly to help ensure that it doesn't leak on the long side.

After some quick math, it looks like primaries in the 30-33" range are probably going to put the torque peak about where you want it for max performance. And run a collector about 12-14" in length. Of course, you can build them to just about any length, and I'm just guessing about where you want your torque peak, although the 223 is kinda limited RPM-wise. I mean, I don't think were going to be seeing any 7500 RPM 223's with torque peak at 5000

 

[texas_rat_trap]

I mean, I don't think were going to be seeing any 7500 RPM 223's with torque peak at 5000

Yeah especially with 4 main bearing caps.

 

[texas_rat_trap]

after some quick math, it looks like primaries in the 30-33" range are probably going to put the torque peak about where you want it for max performance. And run a collector about 12-14" in length. Of course, you can build them to just about any length

I don't know if I'll have the room for those lengths, but we shall see. Also how do you calculate for torque. I was gonna just go by, if it looks good & looks to flow good, then it ought perform good.

 

[godheadcustoms]

There's a couple of school of thought.
1. pretty much what you just stated- and really, anything that looks good will more than likely flow much better than the stock, pinched log. So you will gain a fair bit of power just from the reduction of backpressure, and you probably be able to rev the motor a bit more (again due to the lessened restrictions).

2. use science to help you decide exactly where you want a torque boost. This is really the way to go if you are going to the trouble of building a custom set of headers, although it can be ALOT more work. And everything is a compromise. You may not be able to run primaries as long as you would like to due to space constraints, etc. But there are some fairly complex calc's to find out just how long to make the primaries, collectors, stepped or not, etc, etc.

By going the second route, you can tune the exhaust for a boost at one rpm range, and then tune the intake for a slightly different one and get the benefits of a broadened torque range. The end result is a possible gain larger than the sum of the parts. But beware, going down this road can lead to mind-numbing math, the desire to totally redesign the entire motor, and a fear of actually commiting to building anything because you know, just around the corner, you will have a breakthrough of analysis that will change everything you have designed up to this point. Meanwhile the car sits idle...

Most shorty headers will flow plenty, but the "tuned" length of them is probably somewhere around 7000-8000 rpm. So, while you get the benefit of smoother flow, you are loosing out on any real scavenging effect, which in turn is directly related to how well the intake flows. I think it was Vizard who said the most important tuning aspect of the intake tract, is the exhaust system. Pretty heady food for thought.

To answer your question, there are plenty of exhaust calc's floating around the internet to help you design a header. Try header design . com, for one. I think HRM or PHR had an "exhaust science demystified", or something real close to that title, on their online database. Coincidentally, it was written by Vizard, IIRC.

 

[godheadcustoms]

oops, double post.