oil consumption

I work in a shop we rebuilt a motor in a 96 impala ss it has a LT1 motor. We are now having an oil comsumption problem oil is seepin on to the valves and puddling everything is new the heads have been checked twice and have even replaced the intake any advise or comments will be appreciated

Correct valve seal installed? and installed properly?
Worn valve guides?

according to the machine shop everything is correct the heads have been gone thru twice the oil seems to be coming from between the intake and the heads seeping thru the gaskets

Sounds like the machine shop took too much material off the head deck surface and now the intake mating surface is off. You may need a head gasket shim (if it's available for that engine) to bring the heads back into alignment, or you may need new heads to correct the issue.

If you remove the intake and remove the intake gaskets, lay the manifold back on and see how much space is between the heads and the intake, if excessive the end rail ends of the block should be milled to comp for this and/or the intake side of heads, but a lot would have to taken off the head for this to be an issue, usually .020 or more.