Thanks to all for the feedback, rcull, Ben & Todd.
I did find out from Pertronix that the correct part for my use was #1183. They go buy the Delco-Remy number on distributor, mine ( 1110801 7M31 ).
Beware !!! ( Big Surprise ) eBay sellers list three different Pertronix part numbers and they are all are listed for 1938-56 Buick 8 cylinders.
In first entry I forgot to mention I am in the middle of 12 volt conversion with GM alternator. Thank You, Jim D.