If it were a factory 4 barrel car with a lot of desirable options, they can add up to put the value close to comparable E body or 68-70 B body cars.
Starting with a 318 car doesn't get you that high, although I've seen tastefully done ones bring pretty good money.
I've found this guide to be pretty close-
http://www.collectorcarmarket.com/collector-car/prices/1972-dodge-charger-value.html
For example, adding up the options for my 72 puts it within 3K top dollar value (into the low 30K range) of my buddies 73 Rallye 340 Challenger.
Too bad they don't count the hidden headlights and sure grip axle or HIP paint, as I'm sure those affect the value as well.
As always, it's just a guide.
I saw a really nice 72 SE with most of the same options as mine, even the same color on CL after i bought mine.
It was listed at 16K, and it didn't last long.
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The main pain points on these cars are:
1- no one makes repro fenders, and they rust real bad. I have yet to find a single good fender, and at one time I had eight in my possession, and knew of about eight more.
2- besides a hot motor, a bulge hood is probably the biggest value add. Unfortunately they are VERY pricey, and only repro'd in fiberglass.
3- the cowl area is especially susceptible to rust, and although most of the metal can be found either repro or clean used, it's a VERY labor intensive operation, and can easily kill the value all by it's self.
