Start it at 6.0 lbs. I would think that Chev., Chrysler and Ford would love to sell more engines and components, right? NHRA added gawd knows how many new classes to accommodate the 2008-later 'factory race cars' (and rightfully so). So why not add a few more GT classes at the top?
It's strange how things evolve....in the '80's, the GT classes were NHRA's way of getting newer cars into Super Stock with older engines. Fast forward 25-30 years and now it's the new motors that need a home in older cars for Super Stock.
Bob Dylan said it best:
-Al