Hi Tom - Sorry for the delay in replying. Yes I still have the ZR-1 ZF6 trans available.
Note that this is for ZR-1 only, and will not fit regular small blocks without changing the input shaft.
Note also that on this later model (blue label) gearbox your old clutch will work with it, but you must replace your 91' throw out bearing with a later model one, (93-95). your old one will not fit on the bearing retainer tube.

It's new, in the original box. Blue label, (later model design), I bought it way back in the last century, and paid way more than the $2K I'm selling it for.
I bought it as a spare for my 91' when I was drag racing it.
I've had a couple of messages from guys that are interested, but It's still available.
If you have questions give me a call: (772)285-8607

Thanks for your interest, Bob Eyres