quote:
A. Do Big Bore Headers/Exhaust systems increase Horsepower (HP)
B. at low RPM, hi RPM or both?
C. What is the effect on the power band, broader, flatter, more torque at low RPM only?
D. Does a 351-C require some back pressure to funcion better across the powerband? [/B]
A. The Big Bore header by zise is fairly good. But the port matching is many times bad,and needs to be grind-out. The BB mufflers is restrictivee. So, a set of port matched big bore;s and a good muffler is OK.
B. A header has a diameter that creates exhaust speed, and a lenght that creates pulses. This makes the headers to work at a certain rpm.
C. What creates a broader powerband is the lay-out of the headers. So, here the big bore are the same as Pantera original system, a four in to one. Headers is tuned to give better volumetric efficency at the selected rpm. Which can be at max torque rpm, or max Hp rpm. That is up to the engine builder.
D. For the best volumetric efficency, no enging likes back pressure. Well, sometimes a two stroker.
Goran Malmberg.