Classic/Antique Car Repair: 65 caddy bogging down, good luck jack, flomaster

Question
Ok. I was talking to Brad Sears about this but couldn't get back to him. My caddy bogs down after 40mph. Also it hesitates when I accelerate hard. It also acts like its missing. While in Park it runs great.  Idles fine and I can run it over 3k rmps with no issues but only in park. I have replaced fuel filter, changed distrututor,checked fuel pump, checked for leaks and breaks in fuel line to tank, adjusted carb, checked the accelerator pump (seams ok), the exhuast has recently been redone with flomaster and new pipe (no restriction),plugs and wires have less than 1000mls on them. I am at a loss. What else can I check? My next thing would be take it to a mechanic but that would mean failure on my part. HELP!!!

Answer
My guess is that it is starving for fuel at high loads.  You are not getting enough fuel into the intake.  It could be a rusted fuel line that is allowing just a dribble to get through.  Put a little air pressure in the tank, or just blow into it and see if you can get a big stream out of the line.  
That;s all I can think of.
Good luck
jack