I have a 71 Sedan deville with 472 motor
This has been left standing and now the engine appears to be frozen

Any suggestions to free it up?
At present a small amount of oil has been introduced through
the spark plug holes and I am unsure of my next step

 

Leave the plugs out and squirt in motor oil (a couple of tablespoonful won't hurt). Let it soak in, meanwhile remove all belts from the crank pulley and disable ignition (remove the distriutor cable from the coil). Next, try turning the crank shaft by hand using a braker bar. Once the pistons are moving freely, change the oil (and all fluids, as a matter of fact). Now you can crank the car (recharge the battery) to get rid of the excess oil in the cylinders. Put the old plugs back and try starting it up.

If the car was sitting after simply parking it, the carb may be all gummed up, and you'd prolly better off by rebuilding it before you attempt to start the car. Also, pay attention to the brakes, they might be frozen as well. Depeding on how long the car was sitting, you may want to syphon out as much gas from the tank as you can and pour in fresh gasoline. Once it starts running and you start driving, it will tell you if anything else needs fixin', like putting in new plugs and points...

Others will chime in if I've left out something important.

 

belagatyo's idea is well merited .. IMO

however, on the oil part, i like 1/2 a pint of WD-40 per cylinder,
warmed up if possible .. (it is sold by the gallon can)
it has a tendency to get into very tight spots and wick around
the impassible assemblies of rings and bearings ....

CAUTION:
i would NEITHER take it on the highway or do a burnout with WD-40 ...

ohhh .. smoke .. smoke .. smoke will spew after she fires up.

nothing here applies if there was a COOLANT leak into the cylinders ..
it would be a TEARDOWN ...