New VS Old 340 6-pack

I'm only talking about the Intake, Carbs, Linkage, Air cleaner, lines, ect.. that you buy as a package deal for the Small blocks. I think only the small blocks had the soleniod from the factory, no big blocks. (I could be wrong) No one can tell me for certain, from the parts depts of all the places, what caused the change. ? Thanks for any insight you might be able to shed on this question.