383 cam/ setup help

I ran that cam a few years ago, it has you covered as far as botttom end. Im thinking the previous owned neglected or "tuned" this bad boy. My stock 68 RR 383 auto that I bought with 92,000 had no problem power braking. Usually it is something simple thats is overlooked. Especially if you dont know who installed the cam, who played with the heads, who "rebuilt the carb, etc. Start with the ignition, then the plugs wires, carb. You will track it down.