Well i finally got the manifold finished and installed on my car.. factory stock engine 70k miles, stock cam, advanced cam 4 degrees, eliminated vacuum advance on distributor and limited centrifugal advance to about 14 degrees, initial timing 13 degress BTDC.
Carburetors are HIF 4 from 72 mgb. Custom manifold.
After adjusting jets and installing holley fuel pressure regulator set at 3 psi. Car runs VERY strong past 5000 rpm in 1st and 4000 in 2nd at less than half throttle.
Much more torque fron 2500 to past 5000, with stock cam. And much more responsive than stock holley webber 24/36
could probably rev to 6000 but dont want to stress engine