Home › Forum › Ask A Member › Differences between ’50’s era 30, 35 and 40 hp big twins? › Re: Differences between ’50’s era 30, 35 and 40 hp big twins?
Apples, oranges and pears! The 1956 30hp is a 36 cubic inch engine, a hopped up version of a 25 from 1951 to 1955 of the same size. The 1957 to 59, 35 is a 41 cubic inch model, much differnet than the 25/30, but same bolt pattern. The 1960 to ? 40 has a totally different bolt pattern until you get the the later 1970’s and beyond models that used the narrow tower housing, like the 1950’s model.
One problem you will have with dual engines while can’t having one engine counter rotating at the prop, is it will turn well one way and not the other. That was not available back in the 1950’s.
If you found a left handed prop, maybe a Scott-Atwater, and ran one engine in reverse; it would wear out the rear bearing which is a brass bushing, not a ball bearing like in the front.
Just run one engine.