hi there new to this site

is it best to have two 35cc engines or one twin 70cc

in boat atmoment is a mathe 35cc on a gear box running two props

which seems under powerd ?

I myself run mathe engines and they have good power.I would either run the 70cc inline with the gearbox or try to get a single 35cc counter rotated if not you may have problems with torque roll depending on the size of hull your going to use.Mind you a few guys with the high horsepower motors also break alot of flex cables.As i have learned that most flex cables dont last long on motors that produce 12hp+,so the single 70cc may be something to think about when it comes to the flex cables.Now depending on the size of the hull you may be able to use the twin 35's turning the same direction...as mentioned,all depends on what you want!