I can't figure out exactly what engine I have. I know it's a Mercruiser 4 cylinder 2bbl. I was told by the seller it was an 84 or 85. He also told me it was converted to an alternator instead of a stator. This and some supporting diagrams make me believe it is a 470 since it has the same front mount and exhaust elbow. The kicker is that the only ID plate I found on it was on the front right side and was a Mercruise Marine plate but the SN looks like (it's been scratched up) 4773902. This SN matches a 70's model 140 or 120 but none of the diagrams I look at resemble the engine I have ie: the front mount and the exhaust elbow. Does anyone have any other ways I can ID this engine from looking at it. I was able to scratch off some paint on the outdrive which is also a mercruiser and it says 3.7. This confuses me even more since the 3.7 diagrams seem to also match parts on my engine but was not made till 88 which goes against what the seller told me. The other problem with the 3.7 is that it's a GM but the plate on the engine says Mercruiser Marine. Please give any assistance possible so I can buy parts for the right engine and get this boat running. Thank You All.