What should I do to prep by 61 impala 283 small block after sitting for 10 years?

If you haven't done maint. in ten years you got to pull the engine out and go thru it, re-ring and new bearings at least. All new gaskets and rubber(hose, belts) and then you will be good to go.

Then you can check tires, brakes, wiring, transmission, exhaust, blinker fluid. Maybe you should think about just starting a restoration on this beautiful classic instead.

Cutting corners now will just lead to heartbreak latter.

There are a few steps you will want to accomplish. First drain all the oil and pull the spark plugs. Refill the crankcase with new clean oil. Use an oil gun to squirt oil in each spark hole to coat the walls.

If you can turn the engine crankshaft over with a wrench or socked to ensure the crank is not frozen in place with rust or corrosion. If the crank turns freely that’s a good indication the engine with rotate.

Make sure and drain all of the old gas out of the tank and disconnect the fuel line from the carburetor. Install a new oil and fuel filter.

Install a new or fully charged battery and turn the engine over with the plugs out to allow the oil pump to fill all the oil galleries with fresh oil. You should notice the oil light go out as oil pressure is built up. If the oil light goes out it a good sign all the parts are oiled and the piston rings have coated the cylinder walls with fresh oil.

Fill the car with about 5-gallons of gas and have some one turn the engine over allowing the fuel pump to clear the fuel line until the new gas comes out then hook it up the fuel line again.

Reinstall new spark plugs that are properly gapped. NOTE if the engine starts it will make a lot of blue smoke not to worry it is just burning off the oil on the cylinder walls and will stop.

I assume you will want to change all the spark plug wires, rotor and cap before attempting to start the engine. Its best to start from a known condition. If the engines runs turn it off and drain all the water out of the radiator and replace it with new anti freeze/water.

The transmission will need to have the oil changed at some point as well as the brake fluid. However one step at a time.

Having sat for such a long time all the seals and rubber parts will need to be replaces. You might hear hissing sounds under the hood this is the vacuum lines leaking and will need to be replaced.

Good luck my friend.

I would give it a tune up and if you know about carburator , it would also have to be take apart and cleaned. that is how i started a 74 amc hornet. good luck.

Change the oil and filter.

Flush the fuel system.

Cross your fingers.........