Centaurus,
The history I have by Robert Grinsell on the development of the 51 says with regard to the A-36 that it was a beefed up version for the dive bombing role and retained the original Allison. He only mentions that the attack was "near 90 degrees" but due to occassional asymetric deployment of the dive brakes (hydraulic on each wing) causing an unstable dive, and at times loss of control or structual failure, the brakes were wired shut and the attack limited to 70 degrees until the necessary mods were made. I guess the brakes must have been really effective.