Headers vs. Manifolds...............

You ever wonder what the difference is between headers and manifolds? And this is on a close to stock motor, obviously with more cam/carb/intake etc... gains will be higher with headers!! Big Blocks improve alot breathing even more! To the tune of 43 horse over a set of high flowing magnum exhaust manifolds on a stock 440!


9-25-02 Tests 599 - 604. The point of these tests was to determine how good the original 340 exhaust manifolds 2863553 left side and 2863549 right side exhaust manifolds perform against the Magnum exhaust manifolds and last, headers. The Magnum vs 340 tests were done using 2”id outlet pipes because that is the size the Magnum outlets were. Two right side Magnums were run in test 599, followed by two 340 2863553 left side manifolds, followed by two 2863549 right side manifolds all in 2” id outlet trim. Next in test 602 a 340 set left and right was run with 2.375 outlet pipes. Next in test 603 dyno headers in 1.625 primary tube diameter, 38 primary tube length and 2.375 diameter collectors. Last in test 604 2.625 collectors were run on the dyno headers.

Test Notes
9-25-02 Tests 599 - 604 36% - RH, 27.86” barometric pressure, 62º F - 74º F inlet air

All Tests

6000-3500 rpm
Amoco Ultimate 34 total
Holley 4778 700 cfm
Edelbrock Victor 340
Hughes HEV4545AS
Magnum cylinder heads, stock valves no porting
results corrected to SAE J607
Test 599

Magnum right side exhaust manifolds 2” id outlet
Average ctq 361.5
Average chp 326.3
Test 600

340 2863553 left sides 2” id outlets
Average ctq 360.1
Average chp 324.0
Test 601

340 2863549 right sides 2”id outlets
Average ctq 373.4
Average chp 337.0
Test 602

340 set left and right 2.375 outlets
Average ctq 363.0
Average chp 327.8
Test 603

dyno headers 1.625 x 38 x 2.375
Average ctq 396.5
Average chp 356.8
Test 604

dyno headers 1.625 x 38 x 2.625
Average ctq 402.7
Average chp 362.1

STEVIE, as you know a motor is just a

[size=24:0c67f69098]AIR PUMP[/size:0c67f69098]

The RIGHT intake will give more HP than headers on a stock motor with no other changes.


I always CRINGE when some of the young KIDS come around and want to buy something for their car to make it FAST. Most of the time its a CARB. Gotta be BIG.........wrong.....looks cool, butt, not functional. I know they don't have the money to build a complete motor, butt, most of them are sold on what they read in the MAGS.... :barf: They say, YOU have a BIG carb on your car and it runs GREAT..... I say, it's whats UNDER that carb that makes it run great. I always tell them, first thing to do is LET THE FUCKING CAR BREATHE.........if you have limited $$$$$ spend it on intake, heads, exhaust...... I know you have to have the rest of it too, butt, you have to start somewhere and a BIG CARB isn't the answer.


The OLE MAN


PS, WTF was all that about :lol: :lol: :lol: :lol: an OLD FART rambling

I always figgered the closer to 50/50 the intake and exhaust side were balanced the better, and passenger cars aren't exactly equipped with the best free flowing exhaust from the factory. What do i know though I run a HOLLEY 750 3310-1 and an LD340 intake on my mild cammed otherwise stock 360.... My motors are built with what I have not what works! :rofl:

When I was a kid the first thing you'd do was get Cal Custom chrome valve covers, open element air cleaner and water neck and yellow Accel plug wires. The valve covers would never seal, neither would the chrome water neck and the lack of a hot air pipe made the car hard to start on cold mornings.

But it looked faster....

[quote:80a55b0007="Penske"]When I was a kid the first thing you'd do was get Cal Custom chrome valve covers, open element air cleaner and water neck and yellow Accel plug wires. The valve covers would never seal, neither would the chrome water neck and the lack of a hot air pipe made the car hard to start on cold mornings.

But it looked faster....[/quote:80a55b0007]


...Is that the origin of rice?

Let's hope not