I have a 1958 rdsl-20 Johnson Super Sea Horse 35, but the powerhead is cracked around the piston jugs. Attempted to have a shop weld it but they were unable to weld around the jugs. I may be able to buy a 1957 Johnson 35 powerhead, my question is are they interchangeable if I dismantle all the '58 parts and put it on the '57 block? There are some minor differences in the head, but again I would be putting my parts to the '57 powerhead. Looking at the parts fiche, I see that the pistons/rods/crank are different part numbers also. I was planning on changing the heads, but keeping the '57 piston/crank setup and then bolting everything else back up. Any opinions???
