1980 F-11

I acquired a 1980 Alumacraft F-11 Alaskan 2 model. Although old, it was used little & in real good shape. My questions are ; the specs call for a 20 to 45 hp motor. I live & fish above 5 thousand feet. what recommended outboard jet motor? ;; Can a floor be laid in front to make casting easier?

That's a great hull! You will be down 15% power due to altitude. You loose another 20% with a jet pump. I'd research what that vintage 45 hp 2 stroke engines weigh, what your USCG placard indicates as max weight and find the biggest motor you can find that's not too heavy. I never hear anybody say they wish they had bought a smaller motor and make dang sure you have to have a jet. More people want to convert jet to prop than from prop to jet. Jets are for fighting current with rocks where you need the speed to over come the current. Besides that they are heavy, slow, tipsy and suck fuel.