I've got to pull the timing cover off a 340 on the stand in the shop. It's got a used 100k plus mile cam plate on it. Before I take the cam plate off I'm going to see if I can get a feeler gauge in there anywhere around the plate.
Hi YR, You might try spinning the oil pump when you have the timing cover off. If there are no plugs behind the cam plate I bet you will see oil squirting out. I did this and that's what happened to me (flat block and plate). Is it a lot of oil? No. But it will probably make a mess with the cover off. Does it cause a big oil pressure loss? Not in my experience. I ran without plugs behind the cam plate and did not experience low oil pressure. But, during a cam change I spun up the oil pump with the cover off and noticed oil squirting out (40+ psi on the gauge). I put the plugs in before wrapping up my cam change. Just my experience.
