INSPECTION AND REFACING
See Figures 1 and 2
The exhaust valve seats on the 4-134 and 6-226 are replaceable. All others have integral seats. Check the condition of the seats for excessive wear, pitting or cracks. Remove all traces of deposits from the seats. The seats may be refaced with a special grinding tool, to the dimensions shown in the Valve Specifications Chart.
You can replace the exhaust valve seats by driving them out from the bottom with a driver made for the purpose. This requires removal of the engine from the truck. Removal of the head, crankshaft, camshaft and pistons and rods. The new seats should be chilled with dry ice and installed immediately. They are driven into place with a seat installation tool. After installation, they should be ground to a 45° angle.