The valve guides are pressed into the head after the old ones are bored out. If the mechanic didn't cut it back down to the proper height, there could be contact between the spring retainer, seal, and the guide. This engine should have plenty of valve spring clearance, but it doesn't mean something was over looked.
Using a dial indicator, measure the valve lift on the next valve over. Then take the indicator to the bent push rod valve and move that rocker by hand the same amount. Does it travel the whole amount? ( Doesn't matter where the piston is at this point as long as its down the bore) Now, pry down on the rocker till it bottoms out to see how much total valve lift you have. If you can go past the original valve lift by at least .050" or more, you have plenty of clearance and no coil bind or guide trouble.
Pull the lifter out of the block and check for cam damage of crap in the lifter if they are hydraulic. Check the bottom for scuffing or gouges.
You should also figure a way to cool that engine and give it a real break-in. A few minutes at a time is not doing it any good. Use a garden hose in the heater hose inlet and regulate the flow to keep it cool. I have run engines with out radiators for 20-30 minutes this way, just the let the water run into the yard and have a thermometer in the outlet stream to keep tabs on the temp. Keep it warm, not hot, not cold.
I vote for a sticky guide. It doesn't take much to hang one up and doesn't always show up right away. The way it was broke-in was likely a factor, lack of oil, the guides need to break in as well.
Joe
