You describe an intermittent problem of the engine dying while in use...I think. These problems, over the years, have been the condenser in the dist, the coil, the coil or plug wires and lately the pickup in the dist and mostly the spark box itself..
Them places is where I'd be looking.. Over pressuring the carb should not hurt the carb. All that I have had happen is the pressure opened the needle from it's seat and flooded the engine.. Which doesn't seem to be your problem.
You are finding that one needs to troubleshoot and find the problem before replacing parts..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />