1952-59 Ford Head exhaust valve spring caps

I have DO0E heads and on top of the valve springs where the rocker seats are small caps. They are just on the exhaust valves. Unfortunately I am missing 2 caps. Any idea what the caps are called and where I can get them?

 

Those are called valve lash caps. A good machine shop will have them.

 

Thank you

 

For anyone that might need them. alexsparts.com 70's OE SB Ford 302/351w Factory Exhaust Lash Cap Replacements. Sold in singles for $2.57 ea