Someone checked the piston/valve clearance? Hopefully it's a long shot but I had a 383 which similarly hit a wall around 3000 rpm, which was valves smacking pistons.

Thanks to all for the advice, I set the gap on my new distributor today, installed it, set my final at 36.5 degrees. Took her down the road and the car runs like a raped date!!!!! The plate that the pickup sits on in the old dist was flopping all over. Something broke inside or the bushing let loose because the pickup was mobile . Im thrilled. Thanks Gang!!!