What was the original engine type put in Porsche 944s?

It was a small engine. The car was produced in the '80s when engines were typically 4, 6, or 8 cylinders. (A V8 would be an 8 cylinder engine, for example). The 944 came with a 4 cylinder engine. Among 4 cylinder engines of that era, it was on the larger side (that's the 2.5 or 2.7 liter thing), with pretty high horsepower (again, relative to 4 cylinder engines of the time) at about 140 hp. Most 944s came with this type of engine, but some came with a turbo-charged engine which added about 80 extra hp. Sometimes, the 944 Turbo is called a "951" (Porsche's internal model designation), or "944 Turbo", but usually not just "944". The later 944 with the bigger 2.7 liter engines had some other nice technology too, giving them up to about 180 hp.

2.5

2.5 litre inline slant 4. The clutch is on the flywheel, the transaxle is in the back meaning the driveshaft takes engine torque all the time. Some came turbo. Niice...