I believe timing on Pontiac 400 motors is 12 degrees before tdcWas the vacuum for distributor unhooked? Did you feel carb? When hot an stalled out, pull throttle lever on carb an see if fuel enters air horns, l should but a warning on this, lol!! If it's a stock engine l believe the timing should be 8 btdc but don't quote me on that, as mentioned before SBC ain't my thing.