well the L28's with a flat top f54 block is worth about $100 if not then it's worth whatever it's weight brings in scrap, the L28ET with all the goodies should bring about $350 I've bought 2 whole turbo cars for that price each, auto trannies seem to go to the scrap yards, and the manuals are wirth maybe $200 if they are 5 speed ($250 if it's a turbo 5 speed), 4 speeds go for around $50, of course your area might be different, might want to check in with your local Z Car club
http://www.zcca.org