Oil leaking on my chevy 400 small block?

[jimmy]

I have a chevy 400 small block that I have been trying stop blowning oil all over . It start oot leaking around the fuel pump. I have tried 4 different fuel pumps. the last one I thought I had it fixed. During all this time the car started to rough idle. It turn out to be the cam shaft was going bad. When I took it apart I replaced the oil pan, time chain cover& all new gaskets along with a new cam, lifters & timing chain. For serveral day I had no leaks as long as I was driving aroud town, Once I started out on the hwy at 65 & 70 mph the car look like it was on fire. Oil leaking around the front of the intake. I pulled the intake back off & replaced the intake with a new one with another set of gaskets. Now I can see the oil bubbling out through the intake runner gaskets. What can cause this. I stump, with all my years I've never seen this before. I need help