Can anyone figure this out

What's your battery voltage, when switching over from the points ignition to orange box or eqivalent you needed to change over to the new regulator and bring your battery up from 12.5/13 to 14.5 volts. A higher voltage on the primary of the coil will give you a hotter spark also.
Yes with that .509 MP cam 6-7 inches of vacuum at idle is about right so you can usually forget about power brakes.