According to the Collector Car and Truck Market Guide, The value is from $225 to $2750. A 302 only adds 10%. I think this is more realistic than the NADA Guide since very few of these cars are trader through dealers these days.
Sounds like alot,there's a really clean 77 4door for sale not far from here for 1800,been for sale a long time....I got a kick out of my 75 4door when I ran it.Running 12.40's in a4door mav with dogpan hubcaps really riled some folks,others thought it was funny watching it beat 5.0 mustangs & LT1 f-bodies.Had my 15min of fame,I'll back out of here.