At wits end......

Try to make it short.
84 318 police edition engine. Approx. 80k miles. Rebuilt 727 trans from member,stock conv.
Proform electronic ignition 8mm wires. Put mild cam, headers, action+ weiand intake, 650 Proform mech. sec. Compression is average of 120 lbs. in all cylinders. Hooker 1 7/8 headers.
stock fuel pump 3/8" line to engine.
Runs great all day 3/4 throttle.
WOT stumbles/no power
Ive had timing advanced to 53* total advance, and down to 25* total advance. No Difference.

My last guess is springs floating after 4000 rpm. Any suggestions on springs for hydraulic cam?
Ive done this a FEW times before in my lifetime. Its f****** pissin me off.
What do you think??????




Thanks and Merry Christmas.

Dave