Yesterday I checked the compression on my 97 cherokee 4.0ho motor due to misfire codes on cylinders 1 and 2.

The results of the dry test:
Cylinders 1-80psi. 2-150psi. 3-175psi. 4-178psi. 5-174psi. 6-175psi.

Dumped 3 tablespoons of oil in cylinders 1 and 2 and the results were significantly higher which leads me to believe that it is bad piston rings.

My question is what size are standard rings and where should i go to get them.
My cylinder diameter measures out to 3.883in.

 

Standard size is 3.875, Sealed Power E-925K would be one choice. Where/how did you measure 3.883? I believe the largest "G" size cylinder maxed out at 3.8787, leaving you with over 0.004" piston to wall clearance (assuming this is a "g' cylinder), which is excessive.