Thanks for that clarification Terry. But I'm wondering specifically about the V series. Were VF/VR's ever made in long stroke versions? On a separate note, how did those Heli RF & RF-N compare spec wise to the Aero RF's?

Given the alignment pin on most OS liners, I'd imagine that one cannot rotate the liner of an SF 90 degress and insert it into a RE engine either. Of course that would also leave the piston at 90 degrees from it's intended running position in a RE engine (can't get around the position of the piston rod wrt the crankshaft).

David.