88 5.0 LX. Oil was leaking from what appeared to be valve covers. Changed covers. still have leak. Do you have to pull engine to put in rear main seal?
Oil could be leaking from the rear part of the lower intake.
To change the rear main seal you must remove the transmission and H pipe from the car. After that you need to remove the clutch/torque converter and flywheel. After that the seal is exposed.
ghostdog is probably right. the middle section gasket for the stock lower intake is cork and it often fails and looks like the rear main seal is leaking. get a small mirror and climb in under the hood, and look around with a light to see if the rear gasket is leaking.
What is the best way to take off the H-pipe? I have unbolted the pipe from my factor exhaust manifold already. My mufflers look to be welded on. Should I break the weld?
There shold be a middle section you can unbolt to disconnect the H pipe from the mufflers. Sounds like someone might have tried to fix an exhaust problem the easy (lazy) way.
Best thing to fully make sure you know where an oil leak is to due the following.
First purchase a black light from a petstore (for finding pet messes) or a some other place, it should only run you about $20 tops.
Go to your local autoparts store and get some leak finding dye.
Put the dye in your engine.
Run it, then shine the blacklight on it. you'll be able to find the leak easily.
88 oil leak 
