.005 sound way to much,most poeple,engine builders,shops do .002 in order to not compromise the water,compression seals slots.if you take to much then the slot is not deep enough causing the seals not to fit right and you will have problems.

 

From my research .005 is max before the water seals may become an issue.

 

Thanks for the heads up. I am going to order some earls aluminum plugs and tap them for pipe thread. I wish I woulf have known about the company you suggested before I had my plates machined as I would have went with them. http://chipsmotorsports.com/

 

Well, here are the plates with the new fittings installed and painted. Also, what connects to the hole in the iron by the oil fill? I would like to plug it if it is not needed.