The plate is not usually a good option because it impacts the mid and high rpm of the curve. Most factory electronic distributors (and points distributors from '68 up) the problem performance enthusiasts face is the low rpm advance is too long and too quick. This was done to offset the retarded initial timing needed to reduce HC at idle.
First thing needed is to measure what is in there now. Timing tape, timing light, and tach are the things to spend precious dollars on.
Then, if the advance is too quick and long between idle rpm and 1800 rpm, weld and file like I showed Rockable
here
