Weights all over the place?
Some use uncertified scales and most use inconsistent scales at the tracks where they some times use wood plank platforms that are effected by water. I've seen a difference at Englishtown alone from one day to the other scaling my car with nothing touched.
I now only use USA certified truck scales with a half full tank of gas as I race it.

Consider that some makes made by the same mother company like Chrysler will vary some times based on the design. The Plymouth's and the Dodges though they share many parts especially drive train parts and some very little body parts are different from each other in the weight department.
I believe the Plymouth's were a tad lighter than the Dodges and of course the 330 cheap models in either make are lighter than the 500 models.
My 1965' is the lightest of the years for the Dodges as in 330 El cheapo model with every thing manual except the steering in which I converted to manual many full moons back. It is a two door post Sedan. The Sedans are lighter than the hard tops in either make as well.
I've spent and invented many on my car to cut down on what ever fat was there from its birth place at Lynch Road.
Consider it went through a Jack-o-Lee's health spa. LOL.

my 64 with a world product block aluminum hemi heads, dana 60 with ladder bars. a glass hood and a moly cage full of fuel #3125 at milan this year without me in it.

My '65 Coronet was 3450 in this picture. The missing fender, hood, bumper is worth another 100+ lbs. With full interior these cars are usually 3600-3800 in street trim with a big block. You can take weight out of them but it costs time and money.

my 63 belvedere with heater box removed,alum rad,fuel cell w 5 gallons fuel,440 alum heads,727,8.75 went 3280 on digital scales at feed store today.