I pulled this from FieroSails link in our Merchants and Vendors section.
'87 Fiero 2.5L Engine: The following engines can be used in a Fiero except for the flywheel or flexplate. Change induction, exhaust, and electrical systems, pilot bushings as necessary. Will not interchange with '88 engines due to oil pan interference with frame.
Pontiac 6000 '87 2.5L VIN "R"
Chevrolet Celebrity '87 2.5L VIN "R"
Buick Century '87 2.5L VIN "R"
Olds Cutlass Ciera '87 2.5L VIN "R"
The following information was posted to Pennock's Fiero Forum by "Ray" from Houston, TX:
It is possible to get a better 2.5L engine for the '87-88 2.5L Fiero from a 1993 S-10. The 2.5L engine from the '93 S-10 should provide over 100 HP and considerably better mileage.