early 190 eng oil cap. (I meant capacity)

The early ones had an expanding rubber plug, the later ones had rubber can that fit over the oil fill tube.   I dont know when the change was made Lonn.  I would say you should have the expanding plug, the fill tube didnt change so the rubber cap would work.  HTH

The only change in capacity on the 301 would be related to the upgrade to the dual full flow filters (which I don't think happened until the 200) and the change to a crank mounted oil pump, which upped the sump capacity to 16 quarts with the 2 full flow filters changed (I believe the 2 full flow filters came with the crank mounted oil pump).  This oil pan has a big hump up front, where the older engines with the cam driven oil pump has just a more triangular shape that is lowest at the center.  If you google pictures of a 200, 7000, 7010, 7020, or 8010, you will see the newer style oil pan.  If you look at 180s 190s and 190xts, you will see the old style oil pan.  I believe the 185's production ran through the change, so they have both types, thus, aren't a very good reference.

Hurst