Repowering my old 16ft aluminum boat thinking of going 4 stroke but have a question

Hi All i have a 1976 springBok 16 ft boat that’s similar to the starcraft ss that has a 76 johnson 85 v that unfortunately doesnt have power tilt & trim and i hear it can be hard to find the factory unit . I’ve looked at the power jacks like bob’s or panther but there $1600-2700 here in Canada . so unless i can find a used jack plate it doesn’t make sense to spend that much . I’m thinking of repowering with either a 2 stroke from the 90s like a yamaha or johnson or a early 4 stroke from early to mid 2000s

My question is if i go 4 stroke do i go up in power from my original 85hp johnson or go down because of weight. Would a 60hp 4 stroke be enough for a mostly fishing type boat

this is a project boat and i’m redoing the floor with 1/8 aluminum checker plate and redoing the transom sealed with west system epoxy so that will be able to handle the 4stroke

Was the original engine hp rated at crank or prop shaft?

A 1976 motor would not be prop rated.----Your location in Ontario?