[gliding_serpent]

The b&b have 31 inch primaries i believe (plus or minus, hard to measure length from tube center). This in theory might not give max high rpm hp like shorter headers, but would be good for a street build, including a 3.4. It pushes peak torque to near or just above stock rpm, helping midrange. I did not go B&b, but 31 seems to be a magic number (ssi's also use it). Using a generic online calculator that factors in cam profile, stroke, displacement, exhaust valve diameter and a few other things including your desired max hp (i chose 6200rpm)... It told me that my 3.4 with 964 cams needed 31inch primaries and 1.5id. (I expect 275 hp at the fly... Not bad for a mild build). Not sure how useful it was but it confirmed dogma.

If your are building an engine that will rev above 7000rpm, short headers may work better.