As far as the connectors go '99 was the year they went to
one stud, and one plug-in connector.

A few years prior to that, they had two studs.

A few years prior to that, they had two studs with a plastic adapter bolted on...which had two more studs in it...often the plastic adapter had to be removed for retrofit.

Only reason I can remember '99 is several years ago I had to find the connector for the plug in style, due to MP selling the '99-2001 type for big block apps