5/8” drive spark plugs on LA heads

6pak said
Are there any issues with using the magnum type 5/8” drive spark plugs on the older LA heads that had 13/16” drive plugs?
Dia, reach, and gasket all look the same to me.

Nope. I use NKG - BKR6E / #6962 in my 340’s with J heads and eddy heads, stock 318 and 5.9 in my 02 ram.