L-88 would be aluminum heads, cast iron block.
Z-L1 would be aluminum heads and block. Big difference in value.
Post up some numbers and date codes off the block and heads to figure out what exacly it is.
Sounds like it is an over the counter motor?
If you are looking to sell it, you should go over to yenko.net or somewhere like that. Those guys would know what to do with it and probably know who is needing one for the "proper, number matching" resto.
I would still go to yenko.net and ask. Charlie and those guys over there would come closer to letting you know a value. Remember, most of us, pull those motors and set them in the corner so we can go LS....