So i just got done building my 383, everything seemed great but I am leaking a pretty decent amount of oil from the rear main, checked behind the intake manifold and doesn't feel like there is any oil there.

I see droplets from the bellhousing inspection plate, not even 10 miles on this thing.

I had this problem the first time the 383 was built and I also had blue smoke from the exhaust.

this time the only problem I have is the rear main leak and I built this thing myself. Even replaced the rear main twice since the first time I thought I messed it up and redid it with a new rear main. still leaking.

I am worried I may pay someone and the problem might persist.

Could it be high crankcase pressure? any way to fix that? I only have one breather on one valve cover, should I put another on the other valve cover?

anything else to check for or try out?

 

PCV system problem. Get a manometer and check the crankcase for vacuum level.

 

should I feel air blowing out of where the oil fill tube goes if there was excessive crankcase pressure? I don't really feel any.

sorry if anything I ask is dumb, just trying to figure out something I know nothing about.

 

I went to take the starter off and the flywheel inspection plate since I moved my car into the garage and saw more oil on the ground. There were droplets of oil on the bottom of the starter. Then there was some oil on the starter bolts. got the starter off and the flywheel inspection plate. there was oil on the flywheel inspection plate and a good amount of oil sitting on top of the oil pan gasket. was hard to pinpoint without having that area visible. seems like it is just on the passenger side where the starter is.

my bad for jumping on it being the worst possible scenario.

here are some pics of what i found

 

Have the same problem with a fresh 383, I can feel oil coming off the oil sending unit. snugged it the best I could and snugged the valve covers.

 

check back of intake where the intake and head comes together, thats always been a trouble spot.

 

My new 383 is leaving puddles of oil from the rear main area too.

Using my smog pump I blew air into my crankcase (1 or 2 psi deadheaded) and could hear all the places air was leaking out. My crappy stamped steel valve covers will not seal. I'm going to buy cast aluminum ones which are much more rigid. although I don't think this will entirely fix the oil leak.

 

I had the same problem on mine for a little while. It ended up that both of my valve covers were leaking at the back corners. Got new valve cover gaskets(steel core) and tightened down the valve covers really good.