Not really sure of what you're asking but yes, the lower units from either 95 115s will interchange. There was no 1995 140. The heads between a 115 crossflow and a 115 looper will not interchange. Nor will heads from a 140 looper work on either 115.
Now I'm really confused. We're talking about V4's not a V6, right? And yes, the V6's did indeed come in 20" versions. Probably the most popular version.