Quote Originally Posted by Aeroliner View Post
Lower units were short skeg unless you ordered a replacement housing in the basic C configuration with the long skeg.
Alan do you have some documentation of this or just hearsay? I did some research a few years back and determined that most of the last 1,000 serial numbered 20H's have a long skeg; only a few of the first 3,000 have the long skeg ... this appeared to be a pretty consistent pattern. The sense I get is that they ran out of short skegs at the same time they were making 30H lowers and switched production over to the short skeg rather than making more short skegs just for the 20's in 1956.

It is true that after 1956 any replacement 20H housings were long skeg.

Somewhere buried in the Merc service bulletins and APBA Propellor magazines there has to be documentation one way or the other of the change over date where you were allowed to retrofit the long skeg housing onto any 20H. That kind of stuff was and still is very strict in APBA.