Comp XE275HL Idle Vacuum

This grind looks like a pretty decent fit for my 340 with 2.02 J heads, Air gap, headers, and 2500 rpm converter. But, I've got power brakes and steering and am concerned about idle vacuum level. Anyone running this grind can comment on what you see for vacuum? Car is mainly street driven and hopefully some auto-x later in the year.

Use Rhoades variable duration lifters...