For years, I have been reading magazine articles on how headers improve efficiency at all rpm ranges of modified engines. I have even read that they are worth a minimum of 20 HP even in mild engines. Because of this, I am considering adding headers to my 1975 W200. Another selling point is that there are a few exhaust leaks and the pipes are well over 25 years old.
The truck has a 440 which is basically stock. The previous owner installed '915 heads on the motor some time ago, so my best guess is that the engine is around 9 to 1 compression. The cam is stock. I'll be using an Edelbrock Performer intake with a ThermoQuad.
I had headers on another truck I recently parted out, so I'll probably use those. They are full length with 1 3/4" tubes. The exhaust pipes I removed from the other truck are 2 1/2" and have generic Flowmaster type mufflers. I'll be using these too.
Who has installed headers in their stock truck? Did you notice much of an improvement?
Thanks, Greg

Ive ran headers on stock and modified engines for years. Both of my present trucks have headers. The dually is a stock 360 while the shorty has a modified 340. The biggest drawback is the choice of mufflers. Flowcrappers abd their generic brothers are loud obnoxious horsepower robbers..

After seeing some factory manifolds, I don't see how headers can't help. Heres what my 915 headed 440 with a mild cam and around 11:1 sounds like, I like the sound of my Flowmasters, but it is 3" with a crossover tube.

http://www.youtube.com/watch?v=owi1Iv6ZDoI&NR=1&feature=endscreen

Michale

Some one made a set of 1 5/8 inchers IIRC ... try and find a set of those.

He already has headers

A friend put 3" w/flow crappers off headers on his stock 440 which is in a D-300 carhauler and it hurt the power/torque

In 1979 I had an all stock W200 with a 440, 4.10 gears and 36" tires. I drove it 100 miles one way to work.
First run I got 8 MPG, got home stuck on 1 3/4 Hookers with dual exhaust and next trip I got 12 MPG. The stock 440 truck exhaust is junk and headers will help unless the engine is totally in bad shape or untuned.
That truck had Dana 60's at both ends so I put on freewheeling hubs and a part time kit in the t-case, that only netted a 1 MPG increase, the exhaust was the best bang for the buck. That truck would light up the 36 inch tires on bare pavement too after the headers.

Sheldon

Full length headers help torque and horsepower on anything from

a slanty to Hemis and 440s. Carefully check the headers you have

for cracks and thin spots before you install them.

1-3/4 primaries will work well with your setup.