I have an experimental zero-time overhauled Lycoming 180hp Bushmaster, Smith wings, 84/43 McCauley prop on 2250 floats, insured for one passenger because 90 per cent of the last 55 years I flew with one passenger or alone for pleasure and work. It's a good aircraft but like all others its performance deteriorates with load. I haven't flown it on wheels but think your expectations of 135-140 may be high. I would look your Bushmaster over carefully because the price quoted is low; Bushmasters hereabouts are twice that much, often ranging $70- 100k.
The 60 is a coarser pitch, awfully coarse to my thinking, and with the 11 hours and price, I'd approach this one cautiously with both eyes wide open. As for speed, none of the Cubs were built for speed
I had a bushmaster for 10 years and it was a great plane. It would go faster and carry more than a cub. It flew slow, got off short, climbed well but to say it out perfmored a cub is a stretch. Mine had 200hp a constant speed and cruised 120 mph.
Something is wrong about that price. Better be carefull if buying this one.