oversized rotary spark plugs?
 

So I bought a block, here on the forum maybe 7 or 8 months ago. Sadly it has taken me this long to actually get the motor built and dropped in the car. I am almost done with the build, but I have ran into a problem one of my spark plug holes has been re-tapped to a larger size. an OEM spark plug practically falls in the hole. I am stumped to what I can do since I know our spark plugs are so different and so few different manufactures. Anybody have an idea of what I can do without having to pull the motor out of the car again? I had a couple friends tell me about a Heli-coil, which I have never done, nor do I know how to do. pretty much im wondering if I can get some sort of threaded sleeve to make the oem spark plug fit. Any help would be much appreciated, thanks guys

Timesert.... they make all sorts of metal inserts meant for repairing stripped threads. I'm sure if you contacted them with the size threads you are currently dealing with, and the size you need they could figure something out.

http://www.timesert.com/

you can also try this http://www.helicoil.in/ I used helicoil on my girlfriends old car and it worked great. Best of luck to you.