core support/trunk rail stamping

engine/trans/dash: LS23PB278340
rad support/trunk: B8L119063

LS23P B278340
You are missing the year

The data says it is a dart, GTS hard top, with a 340 engine, unknown year, built in Hamtramck, and that it is the 178,339 car built.

On the GTS Registery there are two in your vin range, one could be yours?

So assuming the vin on the dash is OE to the car you have a GTS.

post some photos

This post might she'd some light
Where's the VIN number 68 Valiant