Re-Paint ??... Pro's Chime In....

I have a project in the shop that appears by all accounts to have been sprayed many moons ago (a repaint over the original finish) with Acrylic Enamel & Hardener, no clear coat.

There's a good amount of dirt in the finish.....the car needs to be blocked, a couple small dings taken care of, and resprayed properly.

WITHOUT stripping completely, just properly blocking and prepping, what paint systems will "mate-up" (preferably OTHER than Acryl.Enam.), with or without the use of specified sealers.....? And what, if any clearcoats could then be used to give as close as possible the look of a modern base/clear system when finished?