I'm a red seal technician since 1980 and have done quite a few engines over the years. It all depends on what you want the final result to be, and how much you want to spend. If you want to remain as stock as possible, you can have the crank machined, bore the cylinders a little, new bearings, piston/rings and have a good valve job, (seats, guides and valves plus fitting) Add a bit of a cam( I like Competition Cams) and new lifters, push rods and you'd be good to go. Federal Mogul sells a rebuilt kit with this approach.
If you want more, more, then an Eagle rotating assembly, with forged rods and pistons and crank, gasket set, plus a set of Edelbrock aluminum heads, cam would be potent.
One thing you want to consider is that high lift cams make the car less street drive able. Competition Cams is a great resource and can recommend a nice matching assembly. Edelbrock is also very good at setting you up with a good package.
Big money can be spent if you go aluminum Ford racing block, heads and internals.
This doesn't reflect other things to look at such as exhaust and intake upgrades, which should be considered in a package scenario.
Even a refresh isn't going to be cheap, maybe $2000- $3000 or more, unless you do the tear down and assembly yourself. Good luck, hope this gives you a direction.