I have a 74 Dart with a 360 that has been rebuilt that has oil coming out of the dip stick tube. It has mopar performance valve covers which I think may be the problem but I was hoping someone could help me, I hate to put the factory style valve covers back on, is there any other after market ones that look great that will work better? I installed a new pvc with new hose on drivers side rear with hose going to bottom of carb and a new breather on pass side front with hose going to factory breather. Oil comes out when driving at low rpm's and not at an idle, I have not drove the car much due to not having license on it but I figure it will get worse at higher rpm's. Can anyone please help? I hate to get oil on a new painted motor.

You either have a bad PVC or lots of blow-by.
The engine is building up pressure inside. For your sake, I hope it's not compression blowing past the rings.

Not sure why it would be the valve covers as long as you have the correct PVC and breather.

You didn't by chance overfill it with oil did you? What kind of oil pump was put back in the engine when it was rebuilt?

you might need baffles in those valve covers if they are not there.

Feets pretty much has it. True, non-production valve covers generally have poor baffles compared to stock, but they still they seem to work OK. You either have a defective pcv valve or a defective [ clogged ] breather or extreme blow by. Sometimes the rings get put in upside down. If that's the case, they definitely won't seal. Hope it's the breather or pcv. Good luck.

the pvc and the breather are both new and I don't know what kind of oil pump was installed, it was done before I bought the car. I have heard of others having problems with these valve covers and I was told that mopars build alot of crank case pressure so the motor needs to breath realy good.

Mopars don't have any more crankcase pressure than any other motor. As said you either have a bad PCV breather set up or excessive blowby.

If the valve covers have hols in them for the PCV/breather than there's nothing wrong with them.

I don't want to sound snotty, but you did use a PCV/breather grommet with a hole, not one of the grommet looking plugs right?

We made that mistake once as a kid. That poor little 351 Cleveland blew oil out everywhere.

Is there a way to check for excessive blow by without tearing the engine apart?

the grommet does have a hole and I don't mind you asking because it could happen, I do make mistakes also and I'm not afraid to admit to them.

run the motor. take off the breather. put a piece of stiff paper over the breather grommet. it should be sucked against the grommet. if it doesnt, you have blow by or the pcv isnt working

Too much oil in the crank case?? lower it a quart or two?

How many miles on this rebuilt motor? Sometimes it takes running the engine under load to seat the top compression rings. Take it out and run it hard a couple times and see if that doesn't solve the problem.

I've also got a set of MP alum valvecovers on one of my 440s.

Sometime after installation, after I started driving the car again, I noticed a HUGE amount of oil all over the intake, water housing, etc. So much leakage that it is impossible to determine where it came from.

Thinking that maybe the stainless v.c. bolts were 'lengthening' due to engine heat (and maybe releasing the seal on the gasket), I installed regular steel bolts. No change.

After that I found a thread on Moparts about v.c. baffles (or lack of) in alum valvecovers -- I am next planning to put steel covers back on and see what happens.

To the OP:
Do a compression check. You've got a smallblock and easy sparkplug access, so it's only an hour job. It'll be good baseline data for you in the future anyway.

After that, throw a set of steel covers on and see what happens.

I dont know my kid rums the MP aluminum covers on his OE 62 413.He beats the snot out of it and only runs 2 breathers as I do on my 440 thats built.Neither have any blow back problem.Had a set on his built 360 also with just 2 breatgers and had no problems with it either.I want someon to explain how valve covers can push oil out the dipstick.Unless they are totally sealed its not going to happen.Oil pump wont cause it either as we run hi vol hi pressure pumps in all our motors.Id say the engine has blow by or its not releaving pressure.As said new dosent mean good.Installed too many new parts to know that as I wrench for a living.Rocky

I done a compresion check and all cylinders were 108 to 120 range. I pulled the pvc hose off the carb and it kills the engine. I will take the car out this weekend and run it some more if it does not rain. Thank you for all your help and support.