how to slightly lift '65 barracuda tail end

Your springs are shot out.
Stock replacement springs will raise the car back up to where it should be.
I wouldn't recommend a +1" spring. Ive seen it many times where people weren't happy with
how high the *** end ended up. Go stock replacement.

ESPO is a great company. and has everything you will need for the replacement. Very fair pricing as well.
I would replace the rear shackle bushings while your at it.
Greatly appreciated, I am going to contact them first thing monday. I checked and believe you are correct, the springs are tired. There is a company here that re-stresses springs. I will go chat with them also. Thanks again