OK, here are some things to look for:
VIN should read BS23R0xxxxxxx for a 70, BS23R1xxxxxxx for a 71..
Code on fender tag should say E74 for hemi....trans should either be D21 for 4 speed or D32 for automatic
Should have N96 on fender tag (Fresh air package, AKA shaker hood)
the radiator support (by drivers side of radiator) should have the last 8 digits of the car's VIN stamped in it. Also, these numbers should be stamped in the cowl (drivers side by windshield wiper mech access opening)
Car should have a 26 inch high perf radiator
Car should have torque boxes at front of rear leaf springs and the reinforcements at the rear end of the front frame rails
Car should have the hemi rear suspension and 3/8 fuel line...but these things might have been changed in it's race car former life.
Should have a K member skid plate
Plenty of other little things to look for, but above is a start.
