I'll get the instructions and decal to you in the mail on Tuesday. You may want to coat the decal with some micro decal coating, can't remember the exact name right now but its by the same people that make Micro Sol and Micro Set etc. It's designed to keep together and save old decals. Might not be needed but why take a chance. You could also spray some testors Glosscoat over it before use too.
On these old Stock Cars if you like them there is that whole series of Modifed Stockers from the 60's from AMT that are currently reissued and on the shelves through Model King or Dirt Track Race Cars. These are like the 66 Chevy , Buick Skylark and Olds 88, 65 Fairlane, 69 Torino, 65 Chevelle and so on. .He has also released many of the early 70's nascar series by AMT with an incredible two sheets of Generic decals which carry at least 3 number designations or Combos with numerous sponsor combos, some of which can be cleaverly combined to make actualy replica cars that did run, (a little cut and paste) Out now is the 71 Cyclone, which on the box art has a green GTO passing it in the high groove that is a model lettered by me, 72 Ford Torino and 75 Chevelle Laguna with a 72 Monte Carlo on the way. Many of these can now be obained at your LHS and if you don't have a good one, Hobby Lobby.
Other Annual type kits still availabel have great Nascar versions in the box while the box art doesn't say anything, ie the AMT 66 Ford Galaxie and 69 Torinos which has everything you need to the Dukes of Hazard Charger, which is actually a charger 500. You'll need to fill the grille on that one flush all the way accross and locate appropriate Holman Moody wheels and tires.
Finally check out the Decal Man website. He has vintage stock car kits galore, and the wheels, tires and even Generic but nice roll cage you'll need from Performance Plastic Products.
Dave