sparkplugs first post

I have a '68 hemi roadrunner I picked up around 10years ago. It mostly has been sitting under a tarp in storage since 1970. Its all orignal (30,000 mi) with a fairly new 10 yr paint job. I removed the motor 4 or 5yr ago and had anything that moved replaced. I had the carbs restored and basically have gone over the entire car a restored everything on it. The car runs real good as long as I have new plugs in it. Considering the motor I expect to go thru plugs fast as I am usually driving around in heavy traffic (Washington D.C.) when I have time to take the car out. I have been using the Champion 10 ny plugs but they are hard to find. I was wondering what would be a good replacement "over the counter" plug that I can use as I am having so much trouble finding the factory spec plug.
Thanks
Jim
Author: chelini