A stock 360, aftermarket intake, 750 carb, headers, cam, mild head work...... should easily make 300hp.
In an optimized race car, that would be enough power to run 12.40’s @ 104.
If it was a 90% combo it could run 12.80’s at 101.
13.30 @3400lbs shows about 240hp.
So, if the motor made the 280-300hp it “should”, you have what’s likely about an 80-85% combo.