I went through this about about a year and half ago. Had a warranty, aftermarket, and needed a new motor. Well no more new motors for the sy/ty application were available. This wasn't a definate no at the begining, the had the part number for it ,ordered it and it never showed,reordered still no show. I called GM filnally after several calls got ahold of someone with some knowledge of what were sy/ty specific engines. I was flat out told there were no motors left period. They were to have new replacements made by an independent motor manufacturer because of the small run. I was told they were testing the motors provided for them and would be released soon. I was put on the "list" to get one. Well waited like three more months, called said they made a few and they were taken, and no more were to be made. After waiting so long called warranty company back, right away they had no problem with a rebuilt one to stock specs. So that is what I have now and no problems to this day, besides transmissions, GM replacements, but that is another story in it's self.
Greg