Valve Cover Oil Leaks
 

I have a '65 with a 390 V8 Engine. I wanted to replace the valve covers because of oil leaks. I purchased a set of Edelbrock Valve covers and Felpro rubber gaskets. I have tried everything and have not been able to conquer the oil leak issues. I've managed to get the cover on the passenger side to seal up, but the driver's side will not. I've gone through different gaskets and tried both the old and new covers. I've done my level best to ensure that every surface is clean and free of any oil or dirt. Today I just went to Mac's auto parts and bought a set of chrome covers manufactured to original specs and yet another set of gaskets. Any ideas what I could be doing wrong? Any thoughts? Thanks in advance for your help!

I'm not an expert and I am having the same problem as you at the moment, but I'm still using my old gaskets. Haven't got to buying new as yet. I would use cork gaskets. First put your valve covers on without any gasket and see if the covers are flat and that they don't hit the intake manifold anywhere. If ok use a smear of RTV on the side of the gasket to be used on the cover only. Make shure the gasket sits flat and that the holes line up. Use the bolts upside down if you have to. Let it dry. When ready put the covers on and tighten down. Don't over tighten, only tighten until you feel the bolts stop. Good luck.

This is a huge issue with this engine since it puts way too much oil on the top end and drain-back isn't fast enough to keep up. When I rebuilt mine I researched this and found several articles that recommend restricting the oil passages to the heads.

After I did that my OE valve covers still leaked badly. The thin metal distorts well before achieving the factory specified torque. I've tried "spreaders" on the bolts but that only helped marginally. Using spreaders, a cork gasket, making sure the flange is straight, and using RTV black on both sides of the gasket, torquing to a lower value so as not to distort the cover, then waiting long enough so the RTV cures should work.

Since I want to remove my covers without having to scrape old RTV off the engine surface (tight engine bay, and risk getting pieces inside the engine) I found a set if vintage cast aluminium covers. The cast covers are able to hold the torque without deflection. I use cork gaskets and use RTV on the cover side only. No leaks for me. :driving