Years ago I dyno tested a pump gas 426 M.W. motor with a set of Hooker A body 1 7/8 pipes with a 3/5 collector, the dyno owner made a set of dyno headers for the Mopar wedge motors so he could test them in the future with out borrowing mine. His where 2 1.4 pipes 25 inches long with a four inch collector, I was sure that it would kill the HP and torque down low under 5000 RPM but that stupid motor gained power through out the RPM range shock (we tested it from 3500 to 6500 RPM)
On all A body with BB that I have raced they all have pick up ET and MPH with bigger pipes and open exhaust.
Hedman makes a nice set of 2.0 fender well headers for A body with BB that fit better than the older Hookers do work
Make the rest of exhaust system as big as possible also, 3.0 is way better than 2.5, way better up
If you want a set of TTI chassis headers look at the 2.0 to 2 1/8 step headers, if they offer them, along with a 3.0 exhaust system up twocents

Last edited by Cab_Burge; 12/13/17 04:57 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)