Now my fuel pump is sucking OIL out of the sump

Usually, the gas flows into the oil sump, increasing the volume of oil.

Additionally, if the heat riser valve inside the exhaust manifold is frozen closed, engine performance under load is greatly diminished (aka the potato in the exhaust pipe effect)

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old