My car is very similar to yours except mine is a 68 and has a Comp 292 and 3.23 gears. I was running in the low 13s with a Neal Chance 11 inch 2500 stall converter. Changed to a GER 10 inch that stalled about 3800. With some other minor changes( added carb spacer, changed from 750 vac to DP,dropped about 75 lbs)ran mid twelves with a best of 12.35 at 106. GER converter(cracked flex plates regularly ) has since been replaced with a Dynamic 9.5 but havent run it.