Originally Posted by pmpjohn
The hobby shop will most likely not have large enough sheets of 1/8 ply to do you any good. Go to the lumber yard and get a sheet of Luan ply, cheap and you will have wood left over. Using balsa without glass will not hold up to the vibration and pounding on the water. Motor mounts and all other hardware you will need can be found a Warehouse Hobbies. I gave you the link in post #2 and thier banner ad is at the top of this page. Tony has been building large gas boats for 30 years and knows his stuff.
Warehouse hobbies has alot of parts but nothing for what you need for motor mounts. They only stock for Zenoah.engines. So you better of making your own motor mounts. Both engines in your pic are not the style Homelites to use. So you got you work cut out to make them work. II the engine had a cutch then it would be a breeze for the 4 point mount. You will have to stick with the 3 point mount. A good homelite to start with is a SX135 Bandit motor. The short block is the plat form for all the motors in that series and most comon to find and fix. You don't need RPM to make a fast boat . HP is what you need.