79 200 series Van 318/727.

Sitting at idle its ok. Press the brake pedal and it gets rougher, tries to smooth out but the engine shaking is noticeable since its right there in the vehicle. foot off the brake pedal and its back to normal. Do I have a 'bad' booster ? With the new carburetor I can actually get the engine to idle properly, with the old BBD it was all I could do to get it to run at all sometimes. Before the conversion to 4bbl, just running with the engine cover installed and pressing the pedal at idle I could hear a moderate 'woosh' sound and thought it odd but nothing more. The crappy idle before probably helped to mask the problem.

Booster is a cardone reman from the local store, maybe 3-4 years old at most.