1994 Chevrolet S-10 Engine Swap

you need a 2.2 out of a pickup as it's RWD. you can put a 2.0L in it but would not advise it nothing higher than the year of your truck as it's OBD1 for computer

Here is more information I found on the subject:

Original Engine Options for 1994 Chevrolet S-10
2.2L I4 (L4)
4.3L V6 (V6)

Direct Replacement Engines
Chevrolet/GMC 2.2L I4 Engine: Any 2.2L engine from a similar year S-10 or GMC Sonoma will be a direct fit.

Chevrolet/GMC 4.3L V6 Engine: Similarly, any 4.3L engine from a similar year S-10, GMC Sonoma, or even a full-size truck like the C1500 will fit with minimal modifications.