Great answers from all you guys!!!

I appreciate your reply ted, coming from a man with your knowledge... So, the heads were not machine for positive Seals. I only have umbrella Seals on the intakes. What do you recommend I put on the exhaust valves? Your help is greatly appreciated!!!

Contrary to popular belief, the sodium filled exhaust valves did come from the factory with umbrella seals installed.  Not running any seals on the exhausts in the long term will slowly create a build up on the valve undersides and eventually create other issues.  I don’t stock those particular seals simply due to not restoring those heads with the original large stemmed valves in them.  A shop that works on truck engines should have some of those seals floating loose.  You could also try slipping some 3/8” stemmed umbrella seals over your current valves in lieu of finding the 7/16" seals and see if that works for the short term.
 
And here’s the reasoning behind why not to use those 7/16” stemmed valves in a street engine.  In the truck engines, sodium filled exhaust valves have a life expectancy of ten years as the sodium does corrode or eat away at the interior of the valve stem and makes the valve prone to coming apart.  It’s obviously not a good thing for an exhaust valve head to be bouncing around on top of moving piston.  For what you are doing, a good cylinder head man would have simply recommended installing a new set of 11/32” guides and the appropriate new valves for the exhausts to get rid of the sodium filled exhaust valves.

Lorena, Texas (South of Waco)

What a great reply ted! Thank you for taking the time to write back.. I know you are quite busy....
Richard