Is there a block lift kit that will fit a 69 Barracuda

By the time you get your air shocks installed with extensions on those weakazz 6-cylinder springs, You could have a new set of correct backspace wheels.
Or;
if you have bought 2-piece welded wheels like Rallys, you can get a machine shop to cut them apart and slide the spider over anywhere you want it to be, on that center plateau.