Block Casting number: *297, 313

Aprox. Year: 1996-1999

1 piece rear main seal.

Roller cam engine.

Gen VI, 6 bolt timing cover.

Electric fuel pump. 330 hp aprox.

Block Casting number: 14101148, 14093638, 14088548, 10054727, *526

Aprox. Year: 1988-1985

1 piece rear main seal.

Valve covers  bolt down center.

2 bolt main. Has metal timing cover. 

12 bolt intake. 260 hp aprox.

Cylinder Head number: *619, *770

*= last digits

Aprox. Year: 1990-2004

1 piece rear seal crankshaft

Remanufactured Cylinder Head 3.0l 1990-04

#17 for General Motors