Craig; Go with harden push rods and soak the lifters over night in oil, so they are already pumped up. This will help you to keep from bending a push rod. One other thing that I can think of that may be a concern is the oil pump driveshaft. The FE's have been known to break the oil pump driveshafts and if the thin hexagonal shaft flexes against the load of the oil pump it can cause spark scatter in the distributor. Ford power parts offer a more strong 7/16 chrome-moly steel shaft center one. Also you might look around the junk yard for some 352 heads,58 thru 66 ID for the years would be [B8-B9 then C0 thru C6. The letter is for the decade, if you didn't know? Some of these heads had the adjustable push rod set up and can be used on the 390 heads. The heads them self are interchangable.You will have to watch you valve to piston clearance though because some of these came with longer valves. Hope this helps you some.

Vegas