From the people I know that run them the are basically the same. The RLV has less cuts in the front cone and uses an elbow to get the rest of the 90 degree bend so it uses a shorter connector tube to produce the same piston to first cone length.
I’m looking to buy one or the other… doesn’t matter which model. If anyone has an HPV-3 or an RLV-3 For sale please let me know.
Steve O’Hara