$500 ALL DAY LONG !! Snag it.
RM23NOGXXXXXX is a '70 Plymouth Road Runner hardtop, 383, built in St. Louis. I believe that the "6" in your VIN description is a typo.
B-body 8 3/4 rear axle is worth it alone -- especially if it is a 3.55 or 3.91.
Hood -- even though it's a non-Air Grabber, those still will fetch $350 +.
If the pad says *D383*, it is a '68 non-HP 383. No big deal. The only thing that was different between HP and non-HP was the camshaft and the valve springs. Same *906* heads. Those cores go for around $200. The motor will have a steel crank in it too. Also an easy $200 bill. Just a cursory inventory will get you $2000 worth of parts on it. Well worth the initial investment IMO.
Just saw the manual steering box. That's a $100 core - no problem.