The 1st '70 GTO Stocker I remember is Ray Stover's "Kathy's Clown".
A few years back, I began checkin out all the old Knafel Pontiac drag cars. Ran across their '70 GTO. Seems that it did real good & set lots of records. But, it apparently did not run NHRA. Must have been AHRA, or IHRA, since their was stuff wrote on the windows I'm not familiar with.
Their online site shows pics of the engine, with a Thermoquad carb on it. There is quite a bit of info about the car, as well as pics of it.
Todd Kuhn has been the main driver of the only '70 GTO Stocker that I'm aware of, that has been active in recent years. It's 455 powered. That's the '70 hi compression D-port 455HO, with #64 heads.
http://www.classracerinfo.com/Engine...0&MAKE=Pontiac
Bill Eadelis has a nice '70 RAIV GTO Super Stocker.