(1 piece rear main seal) GEN VI This is a completely remanufactured 7.4L 454 marine engine.Gen 6 is always roller cam and roller lifters.It has a 1 piece rear main seal.7.4 454 Gen. VI Engine Generation 6$4,500.00PriceSize*SelectQuantity*Add to CartDetails Short Block (with no heads) Long Block (with heads)