Ron
Two years ago we had the same issue with our BBC kicking back and breaking the teeth off the flywheel. In fact, I have a very impressive collection of 166/167 tooth flywheels!!
What we did to correct the problem was....
1. Switch to a Powermaster starter (Ultra Torque 9400)
2. Rewire the car with 2-0 cables. Yes, 2-0 cables

. They're about the size of a 3/4 inch garden hose, maybe larger. No problem getting 12 plus volts to the starter. I have one running all the way from the battery to the starter and one is a ground running all the way from the battery to the block. The positive does go thru a kill switch.
We run the MSD 7AL3 but do not use the auto retard. It starts much better without the auto retard.
The 2-0 cables may be a bit of overkill but they work very well. If my memory serves me well, Powermaster recommends 1-0 cables if they are over 10' long. In my dragster, they are just a hair over 10'.
It started everytime this summer without one single problem!!