Reading on an rx7 forum I've learned that there are multiple options for the turbo oil drain on an NA engine.

1. I can   weld a bung into the oil pan
2. I can change the front cover to the Turbo 2 one
3. I can drill and tap the NA cover to accept a -10AN fitting
4. I can make a oil metering pump block-off plate that will accept a -10AN fitting

My concerns are that  that option one would put the drain oil below the oil level and add restriction.  Option 2 would upset an already rebuilt engine...  don't mess with perfection.  Option 3 of  the available areas to drill and below the OMP pad and further down on the cover... the slanted section, which one would be better?


Option 4 seems best but it seems a little high and it too may cause some restriction.


Has anybody used the OMP block-off-plate drain idea with any success?
Should I just put my big-boy pants on and take the front cover off and either switch the front cover or drill/tap or tig a bung to the lower section of the front cover well below the OMP pad?


Advice sought.


Regards, 
Bill Mason