Have you done this before on any Nailhead intake? If so, I would be interested to hear about the set up and actual results.
Not on a Nailhead, but I've notched a stock iron Toronado intake; have used the pictured Olds intake; and have used similar notched-plenum manifolds on Pontiac 400 and Chevrolet 454 engines all with successful outcomes.
hogged out 66 spreadbore intake porting by Greg Gessler has a similar notch. http://www.v8buick.com/showpost.php?p=1742620&postcount=51
