If I am not mistaken the V-ROD was copied from the Yamaha VMAX which the VMAX engine was orginally designed from Porsche.
So that being said No the VROD engine was not designed from Porsche the VMAX already claimed that and stomp the ever living chit out of a V-Rod which I have done countless times when I owned a VMAX
The V-max is a V-4.. The V-Rod motor is the Harley AMA racing motor from the VR1000...
Here, this will help you guys..
Harley-Davidson V-Rod