[spinn]

The manifolds are one peice covering the valley. The temp of the outer air gap bottom is the same temp, as the runner going into the head.

If you can lazer temp gun the intake at the different places. Climb out on the fender with the hood off/open, have a buddy drive and take some readings. Idle won't have the cooling fuel mix flowing. Its action time. Might want to take a timming light out on the limb while you are riding the fender. At 35mph under the hood see if that vacuum advance can is hanging the curve high. Do this fender ride at night so you can see the timing mark.

Mopar made more power because they had long 6.123 rods, better bore x stroke ratio , and rod x stroke ratio, and strong shaft rocker geometry. Held down by the worst head selection for flow.