2k will easily do a G16a. Sierra's engines range from the 1L's then changed to 1.3L's in 85 through to 97. Nothing bigger was offered.
Conversion kit from Ben T is $200 delivered:
viewtopic.php?f=15&t=15009There is only 4 wires to connect up, the rest is a few bolts, trim the sump and it is all done. The conversion kit comes with comprehensive instructions on how to drop it in.