I believe the converter is a 3500 stall. The chamber of the 906 has not been altered, so I assume since they are open chamber, there would be some compression gain with the Edelbrocks. The flow of the906 is probably close to the stock Edelbrocks since these were professionally ported. You are correct the two areas I think heads would help is more compression and lighter weight.
I just run the 1/8th, and getting a consistent 7.0 is fast enough for me. Any faster and I will start breaking everything behind the motor. Dad ran 6.65 with a hotter 440 and we broke everything from the engine back!

The other thing I am considering is simply swapping the cam for a slightly bigger one. I know that can be a rabbit hole, but I am probably running more carb than I need now, so a little bigger cam might get me there.

Thanks for the input.