[Toivo]

I had this done.
The standard FE plug with threads isn't a real common size so I believe MOPAR plugs were used, close enough in size.
I can't say that the motor is now 5%, 10% or 15% stiffer due to the plugs, but I haven't had any problems (sealer was put on the threads before the plugs were screwed in), and the little brass plugs look nice winking out from under the headers when I get down there to look (didn't paint the plugs, just the block itself). I did it as a sort of weird offset to the boring I did to the cylinders which in my mind weakened the block, so I wanted to help it some if I could...there there block, it'll be ok.