Gary, Lots of pushed guides here. I always have to preach about it. Anyway the reason IMO: improper press fit dimensions of guide vs bore or overheat approaching 350F + in the guide area/and or bad alloy in the head or failure to heat treat the head at the foundry prior to machine. Unfortunately (on my Intek anyway) mfgrs know there is really no way back once this happens. I disassembled and repositioned the guide . Within an hour it had moved again. Make sure the finned areas of the engine are free of grass or rodent nests. You may have to replace the head assembly.