Re: dual 6hp?
I don't like that style of outboard either. However, to be period correct you are looking at other motors with the same general styling. The Johnson's of that era are more contemporary looking than the Evinrudes. Even a 1961 and newer Evinrude would be better. That "bread box" style is hideous.
If I wanted twins on that boat and I do want a boat with twins I'd look for a matching pair of 1959-76 Johnson or 1961-76 Evirnude 18 hp's or the later Johnson 20 hp. The 15 hp re-entered the line up in 1973 and is too small looking for that boat. It'll look like a pair of toys on the back. Also, the 15 hp will command more money than the older 18 hp's. The twin 18 hp's will probably give you the top end performance of a 25-30 hp, but with a better hole shot and low speed steering control. I wouldn't bother with anything less than 15-18 hp.
With all that said, why not try your 6 hp's? Lock down the co-pilot screw on the port engine and tiller steer the starboard engine. Weight distribution won't be ideal, but you'll get a feel for whether or not the twin 6 hp's will work. What have you got to lose?
