I have been posting lately about this poor running 130.92 engine. At first I thought I had 2 Timing scales, but I don't, so the timing is not the issue.
So now I suspect the carburators.
They look like 34-4 INAT Zenith Carburetors, but when I removed the float to access the needle (screw in nut), it is stamped 'SOLEX'.

What gives? Do I have Solex carburators?

BTW the Stage 1 and Stage 2 main jets are stamped '90' and '110', which is applicable for the Zenith carbs.

And the symtom is no power. Previously PSFred mentioned a possible vacuum leak, but I have triple checked, and can't find any. I even blocked the vacuum port to the windshield washer pump ( I think it is for the windshield washer pump)

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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