If he were to stroke a small block I doubt he'd stroke the 273. It would kind of be a waste considering head avaiablility and the issue of the small bore.
How much street friendly power do you see him easily getting out of the 273? A stroked SB can go 1 hp per cube with ease and 500hp isn't too difficult at all.
By the time he does a cam, intake, heads, carb etc you have to ask what he'll get for all that money and time.