your low oil pressure might also be because of a worn oil pump as far as i know you have to pull the camshaft to take the cam bearings out i don't know how to do it i had a shop put in my new cam bearings on my 350 when i took it in to get hot tanked and check over
Nate


Link to my photobucket for pics of my vehicles
http://s238.photobucket.com/albums/ff17/OldIronChevy/