No Vin = no way to prove/disprove it being a true Z body. Either way you've got a snowballs chance in hell as to finding any number matching parts due to the absence OF a number.
Also, you'd probably be looking into 40K just to get it running if it's as bad as you make it sound. IMO, keep walking. You'd be surprised what craigslist and auto trader classics can bring up.
http://cleveland.craigslist.org/cto/1143142887.html
http://cleveland.craigslist.org/cto/1136927040.html