I have a pretty big oil leak from the rear of my freshly installed 340. It appears to only leak when the engine is running, when you arrive home a small pool of oil about 2 inches in diameter arrives on the garage floor. The engine is new, I just installed it & have done 200 miles. I removed the transmission to access the back of the block because it seemed to be coming from the back right hand side. Thinking it was the plug located there I removed the plug ( & the other 2 ) resealed them with thread sealant, sealed over the top of the cam plug with red silicone & thought the leak would surely be fixed. Well its not, I just started the car after reinstalling everything & lo and behold it still leaks the same amount. Could there be a crack in the back of the block through the casting of the oil feed gallery going to the oil pump?