How to find out the size of a engine without using the VIN?

My dad recently bought a truck it is a 1985 ford ranger but it has a inline 4 fuel injected engine i keep getting asked what the size of the motor is but i can't say because i don't know. The truck is a salvaged truck but the engine looks really new so it leads me to believe that that motor isn't for that truck and also bc when i order parts for it the parts ppl are skeptical that it is a fuel injected truck seeing as that truck is only suppose to have a carburetor. So how can i find out what the size is of the engine without using the VIN or the catalyst sticker? (it doesn't have one)

It's a 2.3 OHC engine.

HI, if you look at the tag under the hood on the radiator support it should say. As well as on the motor most likely. But most likely its a 2.3 L. (2300cc). They did have a 2.0 L but I think that was earlier.

The engine is stamped with a code Google it.