I have an MP book at home, I can get you more information (I have the 390hp MP)
Off the top of my head the heads will be stamped "hi perf" for the 390 (look through the oil filler) The 390 has the sport pac ignition. 8.8:1 compression. forged pistons w/slight dome. I'm not sure about a 440hp 454, I don't recall that. There there was a 502 w/400+.