Curious as to correct Year for these numbers for HP manifolds --->

Drivers Side --->

2951865-1
2843992-1
8671595-1

Passenger Side ----->

2806800
2888879 (On this last manifold it is kinda hard to make out the 3rd and 4th #'s. They could be a 6 or a 9 but definetely not a 0)

Any help would be gateful.