You will probably want to freshen the valve seats at some point and if you are going to run solid lifters then you will need to adjust them "periodicity" for wear. Maybe every 5,000 miles?
Rollerized rocker arms will reduce valve train wear very significantly and a nice set of stainless steel valves is all you need.
Some builders will install bronze valve guides with them which I will not argue with, and some will recommend sleeving the lifter bores but that in my mind was always just optional on an under 7,000 rpm engine.
Virtually any engine builder can build you a 500hp Cleveland now with virtually off of the shelf items.
Dan Jones has shown 4v iron heads with a nice three angle valve job will flow right around 300cfm on the intakes.
Going over 550 or so starts to get tricky.
There are a couple of in car videos of Panteras on the track and if you notice it isn't really necessary to go much over 6,500 rpms.
Their power range is right in that 4,500 to 6,500 rpm range which for this engine is a piece of cake.
Mr.Pence is going to point out and remind everyone I am sure that the initial intention of the 4v Clevleand engine was an easy obtainable 500hp and an engine that revs very easily and safely. I will agree with that statement before he even makes it.
