Help me put "587" heads on a 318

Depends on what you are doing....daily driver, weekend racer or ?

I raced with stock valves for 20 years before aftermarket parts arrived on the scene...

If your stock valves are good use them... I'd have your shop take a close look at the guides and seats. Buy new springs and have the rockers disassembled and cleaned/checked.

The last set of j heads I had done cost me $718.00 out the door. New stainless valves, bronze guides, springs, retainers, locks, angle mill for compression...the works.