i have a 1968 slant six and very low compression. the rocker assembly was dry too so i pulled the head. the oil holes in the block to the head were dry also. i pulled a piston the rings were dry. it was a miracle this motor ran at all! i blew air through one of the oil holes in the block and i heard it escaping at the rear of the block. is the rear oil seal blown and thus not pressurizing the left side of the motor which supplies the head?
i never saw this before.
anybody got a slant six for sale? i'm in oklahoma city.
jim

There is a good chance that the engine has worn cam bearing and that makes it hard for the oil to reach the rocker arms.
How many miles are on this engine?
DD

wow ! thanks you're the first person who has said anything. and the graphic is really helpful too. the engine is old for sure. bored well over stock. i guess next thing is to pull the thing and make sure i can bench pressurize the situation. apply some kind of external oil pressure and see if it can reach the oil holes. i guess i could just put the pump back on and crank it also. heave ho!
jim

Better yet, go under the engine and pull-out the pressure sending unit or oil pump's releif valve, install a hose connection fitting into the tapped hole and apply oil pressure thru that connection.
DD