i also agree, IF you can find VB parts,keep it VB. you sometimes see the VHs on the road but you never see the VBs on the road. plus keeping it as a VB makes it rarer, more unique and more desirable/collectable. Granted, finding replacement VB parts might be quite difficult. I wanted to get a parts car last week for $500 for that very reason but parents were being stubborn and refused to allow me to store it at home.
I know you said you wont be doing a conversion for a while but if you are still interested in dropping a 308 into your VB shoot me a PM and ill take you out in mine so you can see what to expect of the final outcome if you do go that route. Im pretty happy with mine so i say you should do it down the track