Yeah, id bet it was a P&W JT8D-200 (McDonnell Douglas MD-80/DC-9) Turbofan engine (15-25,000 LBS of thrust). Anything bigger, say a CFM-56(Boeing 737-300, 400, 500, New Generation, 25-30,000 LBS of thrust) wouldn't be so small :P . It also could have been a business aircraft engine, say a GE...