I have read most of the entire post. A couple of things come to mind. 1.) what kind of rings did you use. Chrome rings are hard to ceat in and may take a few hundread miles of hard running for this to happen. Cast iron rings would be my choice.
2.) taper wear in the cylinder bore should be checked. I however do not remember how much is acceptable.
3.) did you check how the compression rings fit into the cylinder bore befoe they were instaled on the pistons. There is a magic measurment for the gap in the ring which is acceptable before installing them on the piston.
4.) a sloppy fit of the piston in the bore ( moving the piston side to side ) is not good.
5.) before you do anything more it would be worth your money to get a seasoned mechanic invole. Your truck looks like it's worth the extra $$$$ spent. Best wishes.
