Dual Plug heads

[mrwfp]

I met someone 2 days ago who has a '68 Charger with a non-original 426 hemi that he said has dual spark plug heads.  The second set of spark plug holes for each cylinder had been plugged and after market valve covers with single spark plugs and tubes are now used. He asked if I knew anything about these heads as far as quality or performance.  I don't other than they were used for race applications.  Does anybody here know anything about dual plug 426 hemi heads that I can pass on to him? Thanks!

[heywodja]

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/2550360/426-hemi-dual-plug-heads-p4120960.html