The 235 that's in my panel burned a quart of 50wt per hundred miles. It left a cloud of smoke behind me that was a bit outrageous at times!
I did a ring job, and valve seals myself, with the engine in the truck.
I bought the valve seals for $7 at FLAPS, and got some NOS rings on ebay for $40. I also replaced the con-rod bearing shells too, those were $95 at FLAPS. I think my head gasket was $40.
I lapped the valves too.
I don't burn oil anymore, and I had a great time doing the work. The work doesn't require too many specialized tools. A torque wrench, feeler gauges, plasti-gauge, and a hone, but you can use the cheap hard stone one, instead of the fancy ball hones. I didn't need a ridge reamer, as the ridge in my cylinders was so slight.
The manual describes all this stuff, and right here is a great place to ask questions if you're stumped, or unsure.
I did this about 6000 miles ago.
