How many horses are there in headers?

[folke]

At the present my car is equipped with the same rusty, leaky headers that were on it when I bought it. Primaries 1 ¾”, secondary 3”. Rest of exhaust is dual 3” with cross-over pipe. I presently am quite annoyed over these headers: They are always in the way (e.g. changing sparkplugs, getting at the starter is a minor rebuild project, getting the tranny out requires removing the headers meaning coolant all over the place.......and so on), responsible for countless burn injuries etc, etc.... How many hp would you say they contribute over HP manifolds if I were to keep the rest of the exhaust system?. Engine is 440 .060” over, cam is Crower hydraulic .478/.502” lift 228/236 duration at .050, carburation is Holley 780 cfm vacuum on Performer RPM or Edelbrock CH-28 with dual AFB:s, TRW "Six pack" pistons, stock 906 heads, 4-speed, 3.23 sure

[DartGT66]

I would say that in your case about 10-25 depending on the rest of the exhaust.

[440 Jim]

This is hard to say. But that is a decent performance build 440, so I think switching to HP manifolds will reduce your peak by about 50 hp. But since the HP manifolds flow pretty good at lower RPM, the reduction shouldn't be so bad below 3500. I don't have any dyno numbers to back this up, just gut feel.


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440 Jim
E-Body Fish: 12.8 sec 1/4 mile with stock exhaust manifolds

[Taylor3]

Put it this way, unless you are doing some serious racing all that pain you mentioned is not worth the added value from headers. I have been there. I use good stock manifolds with custom 3" pipes and I can do all my work and keep my sanity. My friends still like me after I have changed the plugs. I don't miss the little extra hp. You decide.

[Runner1971]

well headers are alot lighter than manifolds as well. if you use studes in your head instead of bolts you wouldnt have to drain the coolant to remove a header, when i do a tranny i just drop the right side header and that takes only a couple min.good headers shouldnt leak. and manifolds also put a huge amount of heat on the top of your engine. i burned myself more with manifolds than i do with headers, i also never found changing plugs to be much trouble with headers either

[Cuda Kid]

I agree with Runner. I have plenty of room to change plugs in my car with the headers on and if you find yourself constantly burning yourself on them just let them cool off before you do anything.

[DaMopaGuy]

I am a firm beeleiver in headers, But if you really want to keep manifolds have them extrude honed(or ported, whatever) I think theres a post about this in the rear wheel drive performance tips area. I think headers are worth 20-25 horses and 25 ft lbs of torque, DON'T QUESTION MY AUTHORRATIE! I say thats what the power gain is gonna BEE! UNNERSTAN? GUD!

[This message has been edited by DaMopaGuy (edited December 27, 2000).]

[ramtuff truk]

If your going for bottom end torque,go with performance stock manifolds.If midrange or high revs are where you live,get headers.And cheep headers= headaches,clearance woes and short lifespan of product.

[DartGT66]

Actually the headers help both the top and bottom end. They just work alot better than the exhaust manifolds, unless you go to a very big primaries they will outperform manifolds to 0-10000+ rpm. But the power difference is not that big in a moderate engine; I remember an old dyno test of a 440 where they switched from stock intake, MP 272 cam and HP manifolds to Holley streetdominator, 280 cam and headers, and picked 50 hp in an engine dyno (350 with 'stock' parts and 400 with the mods). This was a 11.5:1 engine and the test was published in an old ('84?) Hot Rod magazine where they built several different power level 440's from 300 to 600 hp, a very good article if you can find it. as far as the weight difference goes, I have weighed a few sets of headers and manifolds, and to my surprise there wasn't a lot of veight difference to talk about. Personally I like headers, and have not had the problems with them most people seem to talk about. No leaks,ground clearnce problems easily solved etc.

[PRO]

The more power your motor makes the more effect a header has on performance,manifolds on your combo will choke it like a big DOG!!!their worth 35-40 ponies on your combo,dont forget that headers help mpg too..PRP..

[PRO]

The more power your motor makes the more effect a header has on performance,manifolds on your combo will choke it like a big DOG!!!their worth 35-40 ponies on your combo,dont forget that headers help mpg too..PRO...