Unless it's a financial necessity, I wouldn't sell it.
It's not #'s matching, nor is it it optioned in any kind of desirable way (as mentioned, not an R/T, Hemi, etc), so the money you would get would be limited. Despite what you might have spent on it, I'd say you'd maybe get $15k for it. $20k if it was immaculate - but realise that '70 #'s matching R/T's are going for $30k, and the big dollars are only going for those that truly deserve it.
I'd say use it more - be that Dad with the cool cars. Use that car as a bond and teach them about it. Tell them if they look after it, then one day it'll be theirs.