250 ENGINE ASSEMBLY GMC GROUP 0 105 CAP Crankshaft Rear Bearing 73 78 All Blazer Jimmy 4 3928975 I 12 30 CAP 4 8 1790A 0 106 BEARING UNIT Crankshaft Rear 1 upper and 1 lower See group 0 096 for modal application y 0 137 SEAL Crankshaft and Rear Bearing Cap Oil 73 78 All Blazer Jimmy 473424 I 8 30 SEAL 8 1670A 0 153 SHIM UNIT Crankshaft Bearing Cap 73 78 All Blazer Jimmy 3911010 A R 3 70 SHIM UNIT cap 1 6 8 1819 73 78 All Blazer Jimmy 3928985 A R 4 60 SHIM UNIT rear 8 1819 0 206 COVER ASM SCREW Crankcase Front End 73 74 All Blazer Jimmy 3988618 1 19 05 COVER ASM 8 2200A 76 CKG I Blazer Jimmy 360910 1 I9 05 COVER ASM 8 2200A 77 78 CKG I Blazer Jimmy 462847 1 21 20 COVER ASM 8 2200A 73 77 All Blazer Jimmy 180018 8 SCREW w Iockwasher cover 8 1490 0 207 GASKET Crankcasa Front End Cover 73 78 All Blazer Jimmy 3923472 I 87 GASKET 8 2230A 0 213 SEAL Crankcase Front End Cover 73 78 All Blazer Jimmy 3980287 1 SEAL 2 0 D stamped 3980267 8 1662E 0 269 HEAD Cylinder NOTE 1 it may be necessary to plug A l l1 holes with 18 pipe plug NOTE 2 Old rocker cvr can be used on new cyl hd The air ditch cvr flange can be cut off or left in plc at the discretion of the owner or service dept For service a past model rkr cvr gasket with the air ditch portion removed can be used but H T IL sealer is recommended 73 74 All Blazer Jimmy 76 77 C 1 Cab w H D Chassis exc inn agar Hd 76 77 C 1 Sub Blazer C Jimmy C exc Intregal Hd 76 77 K 1 Cab Blazer K Jimmy K exc Intregal J Hd 78 All 250 exc Intregal Hd 8259693 I 215 00 HEAD w studs 8 0570A 78 All 250 w Integral Hd 14008883 1 407 00 HEAD cyl note 2 8 0570A 75 All Blazer Jimmy 76 C 1 Cab w lntregal Hd exc H D Chassis 76 G 1 w lntregal Hd 14008883 I 407 00 HEAD w studs Note 2 8 0570A 77 C 1 Cab w lntregal Hd exc H D Chassis 77 G 1 w lntregal Hd 14008883 1 407 00 HEAD w studs 8 0570A 75 77 All 250 w lntregal Hd 14008883 1 407 00 HEAD w studs Note 1 Note 2 8 0570A 0 289 GASKET GASKET UNIT Cylinder Head NOTE 1 Unit consists of 1 Cylinder head gasket 1 Water outlet gasket 1 Valve rocker cover gasket 2 Push rad cover gaskets 1 lnlel and exhaust manifold gasket 1 Thermostat housing gasket 1 Exhaust pipe packing and 12 Valve stem oil seals NOTE 2 Unit consists of l Cylinder head gasket 1 Water outlet gasket 2 Push rod cover gaskets 1 Exhaust manifold gasket 1 Thermostat housing gasket and 12 Valve stem oil seals NOTE 3 This unit does not contain rocker cover gasket Use silicone rubber sealant for engines with HTV formed in place gasket NOTE 4 Unit consists of 1 Cylinder head gasket 1 Water outlet gasket 2 Push rod cover gaskets 1 Inlet and exhaust manifold gasket 1 Thermostat housing gasket 1 Exhaust pipe ring and 12 I alve stem oil seals 73 78 All Blazer Jimmy 465893 1 9 15 GASKET I 8 0630A 73 74 All Blazer Jimmy 75 76 C 1 Cab w H D Chassis 75 76 C 1 Sub 75 76 K I Cab Blazer K Jimmy u 76 Blazer C Jimmy C 345030 1 27 25 GASKET UNIT Note 1 8 0630A 75 78 C 1 Cab exc H D Chassis 75 76 G 1 3 75 Blazer C Jimmy C 358827 1 34 50 GASKET UNIT Note I 8 0630A WAREHOUSING AND DISTRIBUTIONDIVISION OF GENERAL MOTORS CORPORAT 0N LT TRUCK 5I 0 1 050289 04 REV 2 83