Imagine how thrilled I was when I went to the exhaust shop that was recommended to me and a guy comes out and says "I used to have one of those" (C3 vette). I was there to get a quote on x-pipe dual exhaust. I told him I wanted a quieter ride than the glass packs the PO had installed and figured I might as well get headers and the x-pipe done at the same time. He first tells me that he has done exactly that in at least 4 other C3s!... Then he starts telling me that headers are mostly for show and that the ram horn exhaust manifolds would give me as good of flow as block huggers (his suggestion) and only moderately less than full headers.

I am obviously very skeptical about any of his opinions so I was wondering what you all thought. I am mostly looking for a setup that allows me to have a conversation or listen to the radio at highway speed. No stip, track, or shows. I am planning on $500-1000. Just want it to run well without sounding like a Harley.

 

the X or H pipe will eliminate the droning noise that dual exhaust and headers create at speed....my suggestion is to look at the headers that will fit the steeroids rack and pinion application and choose one of those...that way you or the next guy can put in the rack and pinion unit if you want to. mine are the less expensive hooker or hedman longer ones i cant remember which one though running in to CC 2.5 pipes and muffler with an H pipe

 

He is misinformed the shorties will move more air than the rams horns

 

If you had any belief at all in what he was telling you, you wouldn't be posting the question...

Not only is there a big difference in performance between stock (including "Ram's Horns") manifolds and headers, but there's a big difference in performance between various header designs and diameters - I've posted some of those dyno results here before.

As with anything related to performance, everything is a compromise. The factory uses certain equipment (such as cast manifolds) because it provides a reasonable level of performance with good reliability at a marketable cost.

Headers, on even a mildly modified engine, will outperform the cast iron manifolds by about 15 horsepower. I've documented power differences between different header manufacturers and header diameters of over 10 horsepower. This occurs with a sacrifice in ground clearance, sound level, and reliability (headers can rust through, leak, get dented, and tend to hang low). Headers will also require a re-tune of the carb to obtain the best performance level.

If you want a reliable, quiet, comfortable ride and don't care about a 15 hp change, stay with the cast iron Rams Horns - they'll run just fine at a much lower total system cost. If you're squeezing the car for a bit more power, headers are an effective way of gaining an edge.

Lars

 

above posts i think are on the money. fyi stock manifolds and headers are a serious source of heat but ceramic coatings seam to shed the heat A LOT BETTER. hedman ceramic with pypes champered cross over exhaust and would never go back. sounds thoaty outside but I can still hear the radio fine even at highway speeds. am sure lots of other combanations would be very similare results just pointing out my proven ingredients.

doug

oh and motor is mild build (350 hp?) so flowing more for me would prob be moot point.

 

Of course the long tubes will show more HP. But for me they are just not worth having on a true street car. My car is lowered so I need the clearance that the long tubes could not give me(yea I had them on the car too) I did use the 2.5 Rams and on my 327 it is really hard to tell the difference in power and my RAMs sure are quite in side the car but roar out the back and no exhaust leaks!! I would consider the 2.5 Rams for sure!

 

Any V8 car that a person drives that can't tell a difference in stock manifolds and true headers has some serious power robbing problems somewhere else.
And for the first time i get to use a quote from another thread about shorty headers:

C3Paul:

 

If your referring to my response pay attention! I said 2.5 Rams which is not what our C3's came with! I didn't say they made as much power either! Just was not that much difference over all on the street. But then I guess you know how to build and drive the fastest thing on the street huh? NOT! Sorry I responded to this as it was just not worth the time!

 

2 weeks ago we finished the 406 for my 77.
Here are the engine dyno results performed at Britco:

Headers with 1 5/8 primary tubes:
458.0 ft/lbs @ 4100 rpm, 398.6 hp @ 5500 rpm

Dorman 2.5" Reproduction Corvette style exhaust manifolds (not ported)
426.5 ft/lbs @ 4000 rpm, 370.9 hp @ 5300 rpm

I would have liked to try other combinations, but getting this small amount of data was expensive enough.

Hope this helps

 

I read what you said so save the refreshment for a new reader.
And yes I can build a pretty hot street setup so what about it?

 

I installed long tube Hedman headers w/ heat wrap(engine compartment is so much cooler) and 2 1/2" stainless exhaust w/ "H" pipe 18" back from the collector and Flowmaster 50 series mufflers. I can hear the music quite well at highway speeds and I don't have any kind of killer juke box. The RPM will depend on exhaust noise at highway speed-if you have ie; 4:10 gears and are running at 75 mph, or you have 2:87 gears and running at 55 mph. Here in Texas, we go 70 to 85 mph or so on the highway, and w/ the TH350 trans., the engine is yelling alittle. If you have good floor insulation, that will help w/ the pipe noise. But over-all/ultimately, even w/ the original (from the factory) exhaust, and the original (from the factory) music box, my '81 'Vette wasn't the greatest as far as quiet riding w/ the music playing goes. If you want that quiet ride so you can hear your juke box clearly, I'd say load up on noise insulation in the flooring.

 

That was good real info. One will find the larger the displacement of the engine the worst these numbers will be, at the same time the milder the engine and less cubic inch the engine is the less the impact there is from a given size exhaust. But still good info you did here.

 

Thanks for posting this!
I've been looking for years to find concrete numbers that show the difference between the 2.5" Ram Horns vs headers.

I'm a big fan of using the stock manifolds on my C3 but my builder told me that with my 500-ish HP 409 SBC, my 2.5" manifolds would be leaving about 40 HP/TQ on the table and your numbers seem to support that.
Now I'm in the process of installing coated headers. I hope the power difference is worth the hassle.
Thanks!
Elm

 

I have long tube headers on mine and have no real issues with ground clearance, the flange is just slightly visible when looking under the car from the front. I've never had any problems hitting anything.
As far as the "X" pipe is concerned, I had a custom shop do my exhaust with an "X" pipe and didn't like the way the exhaust hung in the "X" area so I had him remake it with a crossover pipe instead. It's very difficult in the limited space between the ends of the collectors and the crossmember to make a good smooth transition. I'm not saying it can't be done, I've seen pictures of some good installations on here, just my shop was having trouble making it the way I wanted it. I've read some comments on the crossover pipe being a little less efficient but does make a nice difference in the tone of the exhaust. Everyone has their own preference on mufflers, I run Dynomax Super Tubo's and find them to be quiet enough for nice highway crusing but still offer a mellow tone. There are definately NOT loud!
I can't comment on the header vs. rams horn hp topic, sounds like you have some good real world data from others. I never ran rams horns with my current setup so can't compare. Some advice I would give is don't let the shop install a 1 piece welded exhaust, if you ever have to remove the exhaust system for work, you'll have to cut it and then have it rewelded. I used band clamps just after the crossmember to join the exhaust, I've had it apart several times and it works great. A little red RTV around the pipes just in case there's a potential for a leak.

 

Here is a pretty good article about how headers work. Enjoy!

edit: Oops! Forgot to add the link! Here it is:

http://www.carcraft.com/techarticles...t/viewall.html



Keep the shiny side up!
Scott

 

My vette isn't lowered & the flanges on my long tubes never drag not even on speed bumps. Your exhaust shop probably doesn't want the trouble of installing long tubes, in my opinion, well worth any installation problems.

 

Its a shame because you don't have to put any dents in them to make them fit.

 

Interesting to read the different perspectives on headers. In my experience headers represent one of the best bang for the buck modifications you can do. I have Hooker Super Comp headers on my '79 with 2.5" dual exhaust with a crossover pipe. The headers don't hang any lower than a lot of other stuff on the bottom of the car. I only drive the car in the summer. If it were a winter car (in Canada) I might stay with cast manifolds, but for a summer driver I would definitely recommend the headers.

 

Can anyone recommend Headers for car that has steeriods rack and pinion. Small mod on motor.

Thanks

 

I have the Hooker Super Comp headers and the Steeroids setup, and they fit fine.