Number of 20H conversion exhausts

[Mark75H]

A question about the number of 20H conversion exhaust towers made came up on another forum and I think it is probably an interesting question. Some people might try to convince a prospective 20H buyer that the conversion exhaust tower is rare. Compared to 50hp fishing motors, it is ... compared to Sorianos or Mark75H's it is not.

As an educated guess I would say at least 1,000 conversion towers are made and sold maybe as many as 2,000, but probably not 3,000 based on the fact that 4,000 20H's were made and not all of them were converted.

The conversion kits came out in the summer of 1959 more than 3 years after the end of production of 20H's. 1958 and 1959 were 2 of the all time peak years for APBA Stock Outboard racing. By 1961 the numbers of racers began to dramatically decline and never rebounded to the late 1950's peak.

The factors involved in this are probably:
-General recession in the economy
-Change in management at Hearst Newspapers
-Lack of availablity of new racing motors at dealers
-Having to buy the conversion kits and a new prop to stay
competitive in the B classes. (Quitting or spending that extra money
probably caused a lot of racers to drop out at a time when things
weren't going that well anyway.)

A fully converted 20H would have the exhaust kit, carb kit and gear kit
along with 55H-1 style pistons and a different prop. Each of these
things was sold separately and I have never looked into the exact total
cost, but it may have been half the $400 price of a 20H when new if
you had to pay labor. My dad was the highest paid mechanic in our
area back then and only brought home $20 a week.

A look at the numbers of racers registered to race in the B classes in an
early 1960's year would probably be another reflection of how many
were converted. It would show a minimum but not be accurate on the
top because of these factors:
-Some racers raced runabout and not hydro and vice versa, some raced both
-Not all racers raced APBA
-Not all racers raced every year
-A few people raced with uncompetitive unconverted motors just for
fun
-A very few racers used Champion Hot Rod motors

If my memory is right, there were 700 to 900 or so racers running in
each of the B classes in APBA thru the early 1960's. This brings us full
circle to the 1,000 minimum conversion exhaust kits estimate.

A few years ago I started wondering about the Mk30H style long skegs on the later 20H's. It looks like about the last 1/4 of 20H's had the long skeg lower unit ... also about 1,000.