383 Exhaust Manifiolds vs. Headers

-
Pateras

Pateras

Well-Known Member
Joined
Jan 2, 2014
Messages
232
Reaction score
54
Location
SW Colorado
Don't roast me, as i spent real time searching this out with minimal results.

I'll just be honest, I'm disenchanted about the next to no options for headers on BRB block in my early A-body. There's a few companies that want a fortune for headers that dont even fit my 4 -speed; I then have to send them off to be modified again. Easily over a grand!

Would it be absolutely blasphemous to buy OEM Magnum exhaust manifolds? This is just a very light street rod. How much of a performance hit would i see by using manifolds? Thanks in advance.
 
Did you ever hear of having factory manifolds "extrude honed", from what I've read years ago it makes a good difference for flow. It's also done on intakes.
 
Manifolds are not a terrible way to go. They are in many cases, a better flowing design then other brands cast iron options. Bear in mind the FAST (factory appearing stock tire) class of racing that go rediculiously fast through stock manifolds. I would take the time to clean up the ports, and collector as best I could and then run a good mandrel bent exhaust system to be as efficient as possible.
 
On every big block that we have put in a street car, we always put on factory manifolds with work done to them that are supposed to have the flow like headers
 
headers suck.
every car I bought with headers the first thing I would do is get the saws all out and start cutting.
headers leak and for us street guys who don't go over 50 manifolds are the best option.
 
An early A is the 64-66 models. 67+ are called late A. You have more exhaust options with the late A vs the early A.
 
Some Mopar-magazine did an extensive test between various manifolds, shorties and headers.
They even tested the HP manifolds. Didn't do much for performance.
I recall the outcome was something like this;

Type: --- Manifolds --------------- Shorty headers ------------- Full length headers
HP: - - - - sucky ------------------- less sucky --------------------- good
Fitment: -- good -------------------- less good ---------------------- mostly suck

:)
 
limelite70 said:
headers suck.
every car I bought with headers the first thing I would do is get the saws all out and start cutting.
headers leak and for us street guys who don't go over 50 manifolds are the best option.
Click to expand...

Manifolds are only better if you are into the restostuff or wont pay for a good set of headers. headers make more hp,more torque and may even save you some gasmoney.
 
1Fast340 said:
Manifolds are only better if you are into the restostuff or wont pay for a good set of headers. headers make more hp,more torque and may even save you some gasmoney.
Click to expand...

saw an adetion of grave yard cars, where mark the wormass squirrel said the old cast hi perf 440 manifolds make as much h.p. on a 440 as headers. he may a lot about mopar, but he`s full of it!!
 
Go with the factory 68-70 HP manifolds. Much easier fit in your car which will run great (big motor small car). Headers suck for the street!
 
limelite70 said:
headers suck.
every car I bought with headers the first thing I would do is get the saws all out and start cutting.
headers leak and for us street guys who don't go over 50 manifolds are the best option.
Click to expand...

Maybe you should buy some better headers....my Hooker Super Comps have never ever leaked in the 8 years I have run them....nice thick flanges are key.

I have a friend who had his intake and exhaust manifolds extrude-honed on his 340 but IIRC it was not cheap.
 
66340SEDAN said:
Maybe you should buy some better headers....my Hooker Super Comps have never ever leaked in the 8 years I have run them....nice thick flanges are key.

I have a friend who had his intake and exhaust manifolds extrude-honed on his 340 but IIRC it was not cheap.
Click to expand...

I`ve ran headers on all of my hotrods and drag cars, w/ no problems. if your blowing header gaskets, you have too much back pressure! the fitment on the other hand----------
 
BB-Dave said:
Did you ever hear of having factory manifolds "extrude honed", from what I've read years ago it makes a good difference for flow. It's also done on intakes.
Click to expand...

i talked to a F.A.S.T guy a while back and he says having his manifolds "extrude honed" did absolutely nothing. total waste of money.


Bear in mind the FAST (factory appearing stock tire) class of racing that go ridiculously fast through stock manifolds.
Click to expand...


bear in mind that they also run big cubic inches and do a ton of internal work and a lot of gear to get them to run that way. the entire combo is specially designed to run through manifolds. a lot more money than the average guy wants to spend on a street car.
 
depending on the power level your after. headers will always make more, on a mild engine manifolds will be fine.
 
The guys that are recommending that the OP utilize the OEM big block A-body
exhaust manifolds are full of beans.

Perhaps the VERY WORST stock manifold out there is the pinched down LH side
manifold that exists for this application only and singlehandedly costs you at least
30 horsepower.

f58727dbaba795afcfa7f7f146bcfd0a.jpg



A company called Accurate LTD was making a modified LF side manifold to directly
address this concern. I don't know if they are still available but if they don't have
them on the shelf, perhaps they could make you one. the difference is obvious.

8f064e6cda127615bd8e730216f889ad.jpg



Comparison photo below.

249b3b04c2cc6ed10b788f0ea8be28ac.jpg



Accurate LTD LH Manifold web site: ....... http://69gts383.com/New_left_side_manifold.html
 
66340SEDAN said:
Maybe you should buy some better headers....my Hooker Super Comps have never ever leaked in the 8 years I have run them....nice thick flanges are key.

I have a friend who had his intake and exhaust manifolds extrude-honed on his 340 but IIRC it was not cheap.
Click to expand...


nope ,wont happen.
my F.A.S.T. duster proves we don't need headers.
thanks for the recommendation.
 
You must log in or register to reply here.
-

Back
Top