I'd bet good money it's a 1974 to 1977 Pace Arrow or Southwind.
Chances are it's built on a Dodge chassis and has a 318 engine (appearing in a number of iterations since 1st introduced in 1955) with the old 727 Torque-flight transmission, arguably the best engine/trans combo Chrysler ever made. Be aware that some 1976 and later engines were built in 2 factories, the Mound Road engine plant in Warren, MI and the Mexican plant (the Mexican engines had numerous problems, many being with bad crankshafts and hydraulic valve lifters).
If pre 1978, it does not have overdrive or the lock-up torque converter, which is probably a good thing because there were many,many warranty problems with the converter locking and not disengaging.
Also in 1978, Chrysler introduced what they called the "Lean-burn" ignition system, which was a disaster. For identification purposes, the "Lean-Burn" module was mounted to the side of the air filter housing directly over the heat riser for the electric choke. Normal engine heat would fry them. The North Carolina State Police fixed this problem by moving the "Lean-burn" module to the firewall and blocking off the opening it was mounted to.
There were also problems with the ballast resistors (1970 through 1983) burning out and making it impossible to start after running untill the ballast was replaced.
Then there was the propensity to stall under partial-throttle operation from a stand-still (1973 to 1979), which caused a safety problem when the engine would often stall when trying to get between cars at an intersection.
All these problems are relatively easy to fix but you should be aware of them (if it has that particular driveline).
It's definitely NOT an Explorer, which had the 440 engine and 727 trans combo and was the 1st MH I had.