If there are no vacuum leaks and engine runs smoothly on all 8 cylinders, is there maybe a engine and or transmission mount
that has shifted or broken. Just a thought. 

Located in Harford County Maryland 

The carb is the Carter WCFB. The shop that did the rebuild, readjusted the valves and timing and it is much better now. Still a little off, can hear one tappet. Thanks to all for the help.

I start everything with a vacuum gauge. I bought a large face one from HF. In neutral my stocker is 19 steady and in drive 17.5 and also steady.
If it seems like it has no power or sluggish I would look to the distributor next. If it’s still the loadmatic you need to see if it is acting correctly with a timing light and a vacuum gauge teed into the line.
Tough in the old days but if you could get on a chassis dyno; drive and accelerate as norm as someone watched the timing going thru the gears you can learn a lot...
Additionally is there a PCV system on the engine? It is a controlled vacuum leak and can be tested with your palm over the oil fill tube and a good seal on the oil dip stick. I had to make one out of leather.. The Carter WCFB is a little different than the standard ones if you have the loadmatic dist also. If the dist was up graded the original carb will not work properly. These are all suggestions of things I’ve found out myself or read about to fix mine to be smooth and perform as designed. Good luck.

56 Vic, B'Ville 200 MPH Club Member, So Cal.