Side plates should be re-nitrided if more than .003" of material is removed or they have been resurfaced before.
This will restore the working surface of the plate back to its factory hardness. This increases plate wear resistance and is a must if you want a lasting reliable engine.
Includes strip, clean, shot blasting, freeze plug replacement, oil gallery plugs drilled and tapped with plugs supplied and a complete surface grind and lapping. Plates are then heat treated to OEM specifications.

Link for pics before and after....
https://picasaweb.google.com/chipsmo...ndReNitriding#


https://www.rx7club.com/potential-advertisers-223/plate-lapping-surface-griding-re-nitriding-949235/

Thanks
Chip U