[25stevem]

Don’t keep driving it even to test it if your seeing signs of the plugs getting wet!
You can wash out the rings and cylinder walls in no time if it’s bad enough!

What Cam is in your motor, or do you know how much hot idle vacuum the motor is pulling?

If your cam has close to or over 225 duration @ .050” then that original primary power piston spring that was used on the 400 motor is too stiff which will make for a rich running primary side.

If I recall right that year carb has a fuel bowl vent or some hole on the top that’s real close to the top of the holder for the power piston hanger.
With the motor off stick something down in there and see if when pushing down you can feel the power piston going up and down also.

If yes then do the same thing with the motor at idle and the motors level of vacuum should be holding the piston once again all the way down.

If not then you have just found where a big part of your poor running condition is stemming from.

Don’t just throw that carb away since it’s a 800 cfm version since it was on a 78 TA.