Split vs Headers

[1949P17BC]

I'm a little confused (so its a good day, normally I 'm alot confused) will a split exhaust (George Asche) perform as well as true Header or does one just look cooler than the other, or is the performance differnce so minor it really doesn't matter, so one still looks cooler than the other.

[martybose]

I'm a little confused (so its a good day, normally I 'm alot confused) will a split exhaust (George Asche) perform as well as true Header or does one just look cooler than the other, or is the performance differnce so minor it really doesn't matter, so one still looks cooler than the other.

An interesting question! There is no doubt that a properly designed header will flow better than a split log manifold, but i've never seen anyone document the difference between the two in real world usage.

But I like my cast iron headers anyway!

Marty

[littleman]

WHAT, is our advantage of having a split manifold , versus headers. Proformance/Sound, looks? Does it matter regarding intake? Or all this stricly visual?

AL

[Allan Faust]

The theory about headers and/or split exhaust deals with a simple principle.... breathing.... the more exhaust that can be vehicled out of the engine quicker, allows better performance.... the difference in speed is what makes the difference between a split exhaust and a header. A header will have "graceful" curves allowing less "friction for the gases to leave (as well as a straighter path) and allow the gases to leave quicker than the split manifold as it is now, ie just split in 2....

Allan

[greg g]

Engines are air pumps, more air in more air out more power. Manufacturers have those thing which restrict them from extracting the most power form a given engine. Cost, reliability, economy, ease of manufacture and ease of maintenance. Thise considerations limit what they can or will do. So the favorite hop up things are to allow more air in, more or larger carburetor throats, and more air out less restrictive exhaust. L head, flat head, or valve in block engines (call them whatever) are poor breathers, they respond willingly to less restrictions. So one of the most economical ways to get a bit more power is to open up the exhaust flow. And as long as you are breathing out easier, you might as well be sucking some more in with additional carbs or throats. In 1956 Plymouth offered a 2barrel carburetor option which gave about 8 more HP over the standard songle throat. A less restricted exhaust would have probably yielded a similar amount. But the carbs were probably cheaper than all that additional plumbing for dual exhaust. Go to carnut.com and check out the specs page. The other thing that these engines respond well to is an increase of compression from milling the heador decking the block or both. You can see in the spec chart that as the compression ratio goes up through the years so does the HP. I am running dual carbs, milled head, and 2 inch id single exhaust with low restriction muffler, and the difference in performance is quite dramatic over the stock engine.

[Guest Nile Limbaugh]

An interesting footnote to this discussion is the fact that it's possible to allow too much exhaust out too fast depending on the engine characteristics. I doubt that it's a problem with engines like ours, but with, for instance, an overhead valve engine with a crossflow head some back pressure in the exhaust system is required to prevent any of the incoming charge to escape through the exhaust manifold.

[Allan Faust]

Like with anything Nile, everything is better in moderation.... the extremes always screw something up.

Allan

[Normspeed]

Yup, the better breathing sure perks up a flathead. For me, the split manifold was a combination of liking old school stuff, plus finding a good deal at a swap meet, plus having a few bucks in my pocket at that moment. Must have been before I hit the beer concession. I can say my 218 out performs any stock flathead six I owned before. Beyond that, I'll bet some real headers might add more HP than mine.

[bob_amos]

If you are going to set up an exhaust system I recommend that you try to copy Norm's (the other Norm) system. I recently heard his car and while it was idling thought he has a small block Chevy under the hood. What a sweet sound that was emulating from the tail pipe. It has to be the best sounding flathead 6 exhaust that I have ever heard. And I make my living repairing car so I have heard a lot of them in my 40 plus years of doing just that. You won't be disappointed.

[Normspeed]

Thanx Bob, I got lucky on that setup. If anyone in my area ever wants to set up something similar I can hook them up with the shop that did mine. It goes from the split manifold to a collector, then a single 2 1/4" pipe all the way back with a Flowmaster. I also had my cam reground locally, and that gave it a lope at idle. Cam specs available if you need them.

[blueskies]

Thanx Bob, I got lucky on that setup. If anyone in my area ever wants to set up something similar I can hook them up with the shop that did mine. It goes from the split manifold to a collector, then a single 2 1/4" pipe all the way back with a Flowmaster. I also had my cam reground locally, and that gave it a lope at idle. Cam specs available if you need them.

Norm-

Can you make a sound clip and post it on the net? It would be fun to hear...

Pete

[Normspeed]

I wish I could post a sound clip but I don't have the equipment or savvy to do it. Pete, did you do your clips using a cellphone with sound capability?

[blueskies]

I wish I could post a sound clip but I don't have the equipment or savvy to do it. Pete, did you do your clips using a cellphone with sound capability?

Norm-

I used a video camera for the first few clips I made, and then after getting a better digital camera I made the rest with that. You can use a free hosting site like Youtube or Dropshots. I've used http://www.dropshots.com/ to hose mine, they have a free download software that converts your clips to a managable size and automatically uploads it to their site for sharing.

Pete

[BobT-47P15]

Yes, if you have a fairly new digital camera with the movie capabiliy it will work just fine. I have a Kodak Easy Share camera, and it will do movies with sound. The problem with movies is often the loading time for people with computers on dial-up. Pete's place might be a good thing to use.

[Don Coatney]

http://www.dropshots.com/day.php?userid=18858&cdate=20061023&ctime=172006

[Reg Evans]

http://home.bak.rr.com/larryblacks/idle.wav

[Normspeed]

The cars sound great. Jeez, I just came up to speed and bought a digital camera this year, and I already need one with more moxie. I'm going visiting for Thanksgiving dinner in the Plymouth of course and maybe I can convince someone there to record a sound file for me. Hmmm, Plymouth...Pilgrims...Mayflower...I think tomorrow is the day to take that Mayflower for a cruise around town.

[mackster]

I am just too eager to post here! I did like the sound of norm flat six. I am really thinking of a flow master set up, now! Hey by the way this is my first post at the new forum. I like it!

[Normspeed]

Welcome Monrovia, local kid!

Have you looked through the members list yet?

[mackster]

Welcome Monrovia, local kid!

Have you looked through the members list yet?

not yet, I am really trying to cath up here. thanks for the welcome (and the kid part too!) i will be brousing for the next couple of weeks trying to catch up with this forum, I have been in the "other" Forum.