We just got finished installing 10 nfm ports in our 83 HC 37. If you have gray ports you will need to fill in the holes because the nfm are just a bit smaller. Also the wall thickness is variable, thinnest toward the bow. In the 2 forward most ports in the main cabin the plywood transitioned from .75 to.5 In the middle of the window. Finally you better be ready to deal with water damage. And also make new indents for the drains.
All that said we are delighted with the result. We sprang for glass and are are pleased with that too. Feel free to pm if you want to talk about it.
