I have the same issue with mine. Mine is the stock original 400 (145k miles), with TH400, 3:08 gears. The car just feels lazy getting off the line. I never checked compression in mine, but I get steady idle, 16 inch of steady vacuum at 650 RPM, Timing is at 12 BTC, new plugs, plug wires and the original quadrajet seems fine (I put a new gasket kit in 2 years ago).Anything I'm missing?