The cylinders are going to need to be measured for wear and your choices for hone or bore and piston size will go off of that. More measuring with the block and crank will be required to check for distortion and to determine the main and rod bearing sizes. Connecting rods will need to be measured as well. If the heads are being rebuilt the valves and seats will need to be measured and cut and the head will probably need to be decked as well to flatten and clean the mating surface. At this point you need to find an automotive machine shop to do this work.
As to the piston rings themselves, that choice will be dependent on which pistons you end up running and what you're trying to do with the motor. If it's going to be a stock to mild power rebuild the OEM or really any decent brand name rings will do. If you're building a motor with aftermarket pistons the manufacturer of those will typically provide or recommend a ring package.
18:05:37 08/09/19
