Headers Versus stock Manifolds

[71green go]

I am debating keeping my stock 1971 440 R/t manifolds.............I have a set of new supercomp headers but like the idea of the cooler running less headache manifolds...
Opinions?.....given that the motor will be warmed up performance wise but nothing too crazy

[A383Wing]

stay with the manifolds...less headache...

no burned plug wires, no leaks, less noise.....

[Cooter]

Manifolds are great........Until you get your ass handed to you by the perverbial 5.0 Mustang and you begin to wonder if Headers woulda been the Difference.....


I don't wonder.....I run Headers, as building in "Performance" without headers is like screen doors on a submarine...

[green69rt]

I am debating keeping my stock 1971 440 R/t manifolds.............I have a set of new supercomp headers but like the idea of the cooler running less headache manifolds...
Opinions?.....given that the motor will be warmed up performance wise but nothing too crazy

Ahh, the eternal question.....how much performance is enough and what are we will to pay in terms of cost, reliability, ease of maintenance, etc. 

Personally, I have had both on a 69 440 charger RT.  Do they add HP on a street machine with highway gears, no engine mods and normal street tires?  In my opinion, it's hard to tell, maybe a little.  You have to do timed runs at a drag strip to prove it and there it will make a difference.  Understand that when adding headers you will need to adjust the carb because the headers will tend to cause the engine to lean out.  I also think they let the engine pull better at higher RPMs (that's what you should expect.)  That's the technical part.

Did I like my headers, yes.  I liked the sound, they did make spark plug changes a little harder but nothing outragous.  As for burnt wires, I just used the appropriate looms and wire guides.  Biggest problem was the starter.  My headers wrapped around real close to the starter and made changing it a real bear, including unbolting the header.  Also I think it caused the starter to burn up faster because of the heat from the headers.

Finally, once you add the headers, then wouldn't it be nice to have a bigger carb to take advantage of the better exhaust, and what about a bigger cam, now you need a high stall TQ (if auto) and then some lower gears and bigger tires on the rear,  you see where I'm going here?  Actually if you car is running good now I would keep the headers on the shelf till you had some reason to do some big work on the engine.  If others give you some good advice on those particulat units then decide to put them on, no rush, huh?

[Rolling_Thunder]

I plan on running HP manifolds on my A-12 clone...    I have some Super comp headers in the garage but am still planning on going with the HP manifolds...    just easier to deal with...     they made good power numbers (ask the FAST guys)   If you plan on making it a nice street car then just run manifolds...     if you need those extra 10 or so hp for your 13.3 instead of 13.4 in the 1/4 then run headers...       (thats how i look at it) 

[Cooter]

I can't believe no one has metioned better fuel mileage with headers.

[GPULLER]

I can't believe no one has metioned better fuel mileage with headers.

I had Magnum manifolds on my mild 440 and switched to headers,  it did wake it up.   I've never really had many problems with headers, with the manifolds I did have troubles with passenger side valve cover leakage. 
Often thought about running Max Wedge manifolds, just for the cool factor.

[terrible one]

I can't believe no one has metioned better fuel mileage with headers.

[A383Wing]

I can't believe no one has metioned better fuel mileage with headers.

wrong...headers actually will give worse mileage......

everyone will have their foot in the gas and tearing up the road because it's makes 100 more horsepower now....  

[resq302]

I can't believe no one has metioned better fuel mileage with headers.

And here I thought it would have been sponsored by "Hooker" headers.   Or was the girl holding it not slutty enough?   

[Challenger340]

I've tried this on the Engine Dyno !

517hp/535 Trq 440, pump gas with 1 7/8" Headers,
LOST,
down to 485hp/505trq using '69 HP manifolds and 3 ft of 2 1/2" pipes
If I recall correctly,
peak Torque only dropped 50-100rpm, but peak power occured like 4-500rpm lower ?

The FAST guys compensate HUGE with goofy top secret R & D, and Cam profiles, to overcome the lesser scavenging.
If you think it's only gonna be 10hp on a 450 hp mill with a shelf camshaft ?
imo
I disagree.  

[BSB67]

I've tried this on the Engine Dyno !

517hp/535 Trq 440, pump gas with 1 7/8" Headers,
LOST,
down to 485hp/505trq using '69 HP manifolds and 3 ft of 2 1/2" pipes
If I recall correctly,
peak Torque only dropped 50-100rpm, but peak power occured like 4-500rpm lower ?

The FAST guys compensate HUGE with goofy top secret R & D, and Cam profiles, to overcome the lesser scavenging.
If you think it's only gonna be 10hp on a 450 hp mill with a shelf camshaft ?
imo
I disagree.  

You are correct regarding some off the shelf cams, but with a cam speced properly, the power difference will be small in the 400 to 450 hp range.  With what is known today regarding cams and manifolds, running headers on a car 13.0 @ 106 mph or slower is like putting a tunnel ram and dual quads on a 12 second car.  It might make a little more power, but it is kinda senseless, IMO

[71green go]

Anyone else have any data or experience which is best?......

[41husk]

I had trouble with headers on the wannaBee.  Mostly leaks.  I tried double gaskets and that worked for a bit.  The worst was burning nuetral start switch wire [lug wires and starters, then you had to pull headers as for as you can to get the starter in and out, even with a mini starter.  I am building a Duster and payed good money for a set of 340 HP manifolds rather than headers.  The little bit of HP loss doesnt bother me. If your not going to be racing the pimple faced kid with the 5.0, I would go with manifolds

[A383Wing]

word brother...same thing here

Bryan

[71bee]

I fought with headers for years & years before finally biting the bullet & snagging a good set of '71 HP exhaust manifolds. best decision I've made in a long time. headers are great if your gonna drag race your car consistantly, and don't mind tearing into the engine compartment multiple times. 

[flyinlow]

Ceramic coating helps with the heat issues. Schumaker tri -y and Hedman shorty header split the difference between manifolds and long tube hedders Ground clearence and trapped starter issues go away while still flowing better and saving the weight over manifolds. Aluminum hedder gaskets have been leak free for me.

[Budnicks]

I guess the easy answer is headers make more HP/TQ, than cast iron manifolds Period, the problems the HP manifold is, exhaust gases reversion pulsing in the common plenum of the cast iron manifolds, this hampers flow dramatically... There is a guy that builds custom performance headers for allot of big name racers wwwperformancewelding.com checkout the information on his site, Mark is a very good guy to talk to, very knowledgeable about exhaust components, pricey but good stuff...  There is a place for both types, the 62-65 Max Wedge & Super Stock cast iron with long individual cylinder cast tubes are the best manifolds but are also $900 for reproductions & won't fit all B-Body cars then $1500 for head/down pipes/cut outs, if you can't make your own, they are the only performance iron manifolds that compare to headers & weight 30#'s each....