The only new replacement springs that I found that were compatible. Available here and in limited quantity.
https://www.marineengine.com/parts/...ve§ion=Distributor+-+Prestolite+Ibm-7013c


Originals compared to replacements. A very good starting point. BTW the slots in the yoke are 1/2 an inch long.
Most cautions and procedures can be found in this topic.
http://www.marineengine.com/boat-forum/showthread.php?447347-Where-can-I-find-distributor-springs-!
https://www.marineengine.com/parts/...ve§ion=Distributor+-+Prestolite+Ibm-7013c


Originals compared to replacements. A very good starting point. BTW the slots in the yoke are 1/2 an inch long.
Most cautions and procedures can be found in this topic.
http://www.marineengine.com/boat-forum/showthread.php?447347-Where-can-I-find-distributor-springs-!