1992 Lincoln Town Car Please Help!

It sounds like a rod is knocking. When the bearing goes bad or wears out, it creates too much clearance between the rod and the crankshaft. This 'gap' is what causes the KNOCK when the crankshaft starts turning. The engine can be rebuilt but this can end up being just as costly as replacing it. You may need a new crankshaft and/or a rod. My recommendation would be to replace the engine. At least with a short block. This is just the lower end of the engine. You can re-use your heads, intake, etc. This is probably the cheapest and most dependable way to fix your problem.