Used from 1972-1989 on virtually all OMC & Mercruiser 3.0L 140hp power plants. (both companies used the same GM blocks, but OMC used bolts rather than studs at the end of the crankshaft to hold the couplers on until 1986 in the cobra applications... regardless the crankshaft stayed the same through all of this, but had 3 different commonly stamped part numbers which are all interchangable)
This is for engines with a 2-piece rear main seal....which is what they used before 1990...
No studs on this (which you shouldn't need unless it's a cobra application)
OMC Part Number 0908614 / 908614
GM part # N398775 / 398775 (Stamped)
Equivalent GM Part numbers (Other common Stamps
N9341352 / 9341352
N398776 / 398776
N393775 / 393775
Sometimes looks like 393776
