Will a 99 2wd Tahoe 4l60e that was bolted to a 5.7 vortec
Work in a 2000 Z/28
?

 

No, the '99 5.7 Vortec is an SBC derived engine and would therefore come with an LT-style 298mm input shaft 4L60E.
All LS engines will only bolt up an LS-style 300mm input shaft 4L60E.

It requires an extensive rebuild and many different parts to switch an LT-style into an LS-style trans. This would cost much more than buying a used LS-style trans even if the LT-style was free.

 

FTI (Converters) just reminded me that they can make a custom converter that adapts a 298mm 4L60E to an LS engine.