67 Cuda: disappointing dyno numbers, need some advice!

JMO, that's a 350ish HP engine on a good tune up unless the heads are exceptional on performance. With the 450 lift, bad lifter angle and rockers that are rarely at the true 1.5 ratio, the valve is likely seeing something in the .420-.425 range

About where it should be for RWHP is my guess. Might scratch a little more out on the tune up.

Steel crank??? All 360 factory cranks for that time period are cast. Usually when that "term" is thrown around it implies a forged unit which is highly unlikely in this engine.

Heads, intake and camshaft are ares to investigate to get the RWHP where you want it.

Agree with PRH, somewhat new build and the rockers look like they've never seen a hot tank.