You need to focus on curing the oil leaking into the intake ports from the valley gasket, that can be dangerous(detonation) as well as kill a bunch of power I've seen over .2 ET increase by sealing the intake up so it dryed out the oil sucking into the ports. Lay the intake on the heads with no valley pan and use a feeler gauge at the top and bottom of all four corners to find out how much gap you have at each location(write it down at each location) then have a good machine shop cut the intake so it will set square on the heads so it will seal up properly