Has anybody used these spark plug adapters?

[mopar_nut_440_6]

I was curious if these actually work? The add is as follows.

I have a new product that will make our big blocks with factory cast iron heads run better! These are spark plug adapters to allow the use of 3/4" reach modern plugs instead of the less than par 3/8" reach factory style plugs. All of the modern after-market aluminum big block heads use the 3/4" reach plugs and with good reason; these plugs are superior, burn cleaner and there are many more variations avail. These adapters are simple to use and just screw lightly onto the 3/4 reach plug of your choice, then screw the plug into the head and you are done! Can't get any simpler than that! Also these plugs will fit early LA and poly engines too or any engine that uses a 3/8" reach plug. Your performance, gas mileage and quicker starts will be noticed and no more glazed-over plugs!New This is a set of 8 adapters.

http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=5147231&an=0&page=1#Post5147231