Check out the hybridz forum at www.hybridz.org. There is a forum for stuffing fomoco engines in z's.
Isn't the 351 windsor a big block engine? If so, while anything's possible, you'd be much better off going with a 302.
A 351 Windsor will fit just as well as a 302. Greydog must be thinking of a 351 Cleveland. The site he suggested is a good one for info. I did meet a guy in the pick-n-pull who put a 302 V-8 w/T-5 speed in a 1981 280ZX turbo. He said it wasnt all that difficult as he modified a couple of transmission mounts into engine mounts to bolt the V-8 into the car. I wish I had gotten more info from him, but it was threatening to rain.