It sounds to me like somethting else is wrong besides the regulator. Even if the fuel pressure regulator wasn't working, you will still get some fuel flow to the bowls even if the regulator doesn't increase with boost. It would still have nearly full fuel flow at 0psi of boost.

Do you have an A/F meter on it? Does it go fat or lean? Is it possible the spark table is screwed up causing it to do something funny when it gets to 0psi?

Are you stomping the pedal on the brake and it dies, or are you easing into it and it dies? If I stomp mine, it bogs and doesn't really recover at all, I need to foot brake it a little before getting on the brake.