Mitsubishi: 1991 eclipse 1.8 l M/T

I have a 1991 eclipse how do I know which bolt motor I have. I'm looking
for a new engine and some sites are confusing me if anyone know please
help me out. And also would a 2.0L engine fit in my engine compatment and
what would i need to do that. Thanks for all your help
Eric

I'm sure that an engine swap would be somewhat involved. If you were to
find a junked 1991 (or near year vehicle) with a 2.0L motor in it, the
swap would be much easier. The engine mounts, computer, wiring harnesses
may be different between the two motors. I'd suggest looking up parts
like that on different parts sites like napaonline.com, partsamerica.com,
or genuineoem.com to see if they really are different. If they're not, a
swap to a faster motor may actually work out.