87 supra turbo need expert opinion!

[night-rider]

Ok so heres how it goes, ive known my head gasket has been going for about a week now all the usual symptoms occuring but ive been taking it easy on her, so i was driving it on my lunch break a few days ago and everything was fine, i parked it shut off fine everything was normal heat wasnt up or anything then i went to go start her up after work and it just went ka klunk! like 2 clunks not even like a dadadadaada from the starter then i tried it after that and it just clunks once, i thouhgt my engine had seized but i pulled it into the shop and i watched the flywheel when i tried so start and now it just jumps back and forth within about an inch, we also tried moving the crank pulled clockwise by hand and i could move it about an inch. What could be the problem here valves hitting or what the thign that gets me is that it was running fine when i parked it?