When I bought my 72 model V20 steplift, it had a 72 model 85 hp Johnson. Tried it out with that motor and immediately traded it for a 73 model 135 Johnson which ran great. I recall the 85 Johnson showed about 28 mph on an old airguide speedometer and you could throttle back a bit and still stay on plane. I really wanted to cruise at 28, not have that for full throttle. If I had a 90 that ran well, I'd use it. Keep in mind the older boats had saddle tanks that held just 40 gallons and the only equipment on mine was a compass and speedometer.

what size prop on the v 20 90