I got out my big flat blade screwdriver (you know the one that doubles as a prybar.) and my 2lb hammer placed the flat blade of the screwdriver on the end of that bolt and beat the living **** out of it till it gave up. PB blaster helps the process along but most of it is just brute force.
94 Z28 A3
Direct Port, TH400(The 400 club), Strange 12 bolt
Scattered block coming soon.