Simply put, these are the best U20 production valves you can buy.  Top Quality USA CNC  production!  
 
Improved head design for better flow than obsolete Manley and  Nissan OEM valves.  Swirl polished Stainless with undercut stems.
 
Far superior  in every way to high profit  Manley valves from DatsunParts and cheap failure prone valves from China/Taiwan/India. 
 
Design and precision machining performed by experts who have been building U-20's for 30 years.  Not a low cost, budget OEM copy.
 
Don't believe Dean's  webpage nonsense - his products simply don't compare!
 
This is a set of 8.  Contact us if you need smaller quantities.
 
Money back if you don't agree these are superb!