Different frames...different bikes.
V-Rod is a watercooled cruiser.....Street Rod is a naked street bike!
I took a hard look at the Street Rod when I bought my FXDX...Sport was much easier on this old man body (hands and wrists) than the Street Rod was.
Fun bike to ride though...I liked it better than the V-Rod.
Ride em both...you will see the difference for sure then.
Ride safe.
Crow