It's more than likely a 352 or 390 and they look identical. If it has the OD, it should have a freewheel lever under the dash that looks like another ebrake handle, and if you look at the top of the gas pedal it will have an electrical switch on it. If you have the floor shifter it is more than likely non-OD and a 4 speed with the granny low gear. Basically a 3 speed with a low pulling gear in the 1st position.
As for what to expect, mine rides like a car, smooth as silk, and has plenty of low end torque. It's a pleasure to drive if your looking for a light duty truck. Yours being a 4 speed may have a heavier
suspension but if you don't need the carrying capacity you could lighten it up and it will be a great little truck.
Now I have to go outside and put the hood and grill in, so I can get some lights in the front of this thing
It's been Hell night driving with no headlights j/k