Actually a 68 Valiant. That was the first engine. Closed chambered 516 heads hyd Comp cam .525 lift RPM manifold. Ran low 12s in street trim. Changed to RPM heads, 590 mech cam and Proparts headers. Went low 11s in street trim (complete exhaust and interior)
You may have the mounts turned 90 degrees or even 180.That will bring the motor forward about 2 inches. Made that mistake myself. Also did it come with the shim pack? I used the shims to level it once it was in. Do you have a picture of the drivers side?
Here are some flow numbers for BB Chrysler heads. Early heads pre 66 are not even listed except for Max Wedge heads. Numbers speak for themselves. Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software
Technology ruined golf! 400 yard drives and every hole is driver wedge. They need to limit golf ball distance or club size. Watch the old golf films between Palmer, Nicklaus, Miller and Player. Try hitting a 1 iron into a green!