What year is this Volkswagon engine 043 101.101a?

There are two major numbers on a Volkswagen engine. The first is the engine serial, which is stamped on the boss for the generator stand. It will read something like "AE 4225147." (The most important part of that is the letter or letters at the beginning of the serial number. There's a breakout of these letter groups in John Muir's "How to Keep Your Volkswagen Alive"--and he also lists the timing for each engine series.) The other, which you found, is the part number. 043 101 101a is a dual-port 1600cc engine--which dates from 1970 until end of production. Also, year of production really doesn't matter on a Type 1 engine since once VW designed an engine, they didn't change the way it was made.

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