will crate motor # 12568758 work in 1989 corvette

If you are getting it through Chevrolet, the parts book will tell you the correct application it will work in. Any motor can fit in any car if you have the skills and money to do it. If it is the same block, ie: 350 vs. 350, and your parts will fit on it, yes it will work. There is an article in Vette magazine a couple months back telling the readers how to fit in a new style motor in older Corvettes and what is needed. Worth the read. The July 2015 edition has a LT1-powered 71 build featured on page 20. It may be on the news stands now. There is an older one a few months back showing how to do the swap with crate engines. The February 2015 edition has a LSX 376 crate engine article ready for drop into a C-3 Corvette starting on page 46. Good luck on your project.