I own a shop, and where did you say you had that thing parked? I need some stereo equipment really bad man!
Do this; work the throttle by hand while you look down the carburetors throat to see if its getting fuel. You may be out, or the pump headed south on you. If fuel is present, then pull a plug wire, and hold it about 1/16" away from a ground source while someone trys to start the engine. You should have a good blue spark. Oh yeah, it will shock the crap out of you, if you don't use something to hold it with. If there is no spark, or a very weak red/orange spark, then remove the distributor cap. Turn the engine over, and watch the rotor button to make sure its turning. If not, then suspect the timing chain is bad. If its turning, then check to make sure you have power to the + wire on the coil, and that it hasn't fell off. Check to see if the coil is putting out. If it has a points type distributor distributor, then check to see if the points are breaking when the engine is turned. Often people will install them & not put any lubrication on the distributor cam, and they won't break releasing the coils charge. If it has an HEI distributor, and you have no spark, then remove the rotor button, and inspect it carefully for carbon trails on both side of it. They have been known to short through the center to the shaft, and not fire. Next; If after you have done all of this, and still didn't find anything, go get a new ignition control module. It sits under the rotor button, has four wires, and is held in place by two small bolts that have a 1/4" hex head on them. Don't forget to use some heat sink under the new one, or it will burn out pretty quick if you don't. It comes with most of them, but some don't, and you have to buy it seperately. This should resolve your problem. You may even have a plugged up fuel filter, if there is no fuel to the carburetor. Check this by removing the line, and bump the starter over a little to see if it pumps fuel.
Starter shims are only necessary on the ones that don't engage properly in the flywheel. If it spins over ok with a good battery, and the ignition timing set right, then you don't need shims. Its very rare to find one that needs to be shimmed. If I bought one that didn't won't to work, then I would take it back and get one that did. They did make some that had to be shimmed, and it must be done using a large paper clip to set the proper mesh beween the teeth of the flywheel, and the starter drive. It's shimmed out until the paper clip wire will fit between the lower groove (between the teeth) of the flywheel, and the high tooth of the starter drive. Too tight, and it doesn't want to turn the engine, too lose, and it will eat the gears up, and make a banging noise when you engage the starter. You must put power to the terminal of the starter solenoid to hold the starter (drive) gear into the flywheel while you check it with a gage (paper clip) that is about .040 - .050" in diameter.
Glad to help out, Good Luck!!!