NastyZ28.com - the most comprehensive numbers decoding site on the net   Camaro LT1 Z28 Engine Specifications

1970 engine is used as the baseline. 1971 & 72 will be identical except where noted
1971 had compression dropped from 11.0:1 to 9.0:1 by using different pistons and bigger CC cylinder head.
1972 is identical to 1971, except horsepower dropped 10 and rating was changed from GROSS HP to NET HP.
This engine was incompatible with Air Conditioning. You could NOT order a vehicle equipped with this engine along with Air Conditioning. This is why NO Z28 prior to 1973 has air conditioning.

1970 - 1972 LT-1 Engine

Chevt LT1 350 Engine

1970 Z28 Engine - LT1 360hp (gross)
Casting # GM P/NDescription
Block3970010 4 bolt main, suffix codes: CTB, CTC
Crankshaft 330550Forged steel
Heads 3927186 63.995 cc, 2.02/1.6 valves, screw in studs & guide plates
Cam 3972182 3972178 symbol: (1) square Solid lifter - 0.458(I)/0.484(E) lift, 317I/346E duration
Pistons Domed type - yields 11.0:1 compression
Intake 3972110
Carb (A/T) 3972120Holley List 4490, 780cfm , 4150 series - 4BBL
Carb (A/T) 3972122Holley List 4554, 780cfm , 4150 series - 4BBL w/NB2 (Calif)
Carb (M/T) 3972121Holley List 4555, 780cfm , 4150 series - 4BBL
Carb (M/T) 3972123Holley List 4489, 780cfm , 4150 series - 4BBL w/NB2 (Calif)
LH Exhaust 3942527 2.026", Rear Outlet, AIR
RH Exhaust 3946826 1.96", Rear Outlet, AIR
Distributor 1112019 single point w/RFI
Alternator: Delcotron 37 Amp, part # 1100837
Water Pump: 3953692
crank pulley: 9956668 coded CG
Deep Groove Water Pump Pulley: 3995647 coded AP
Power steering Pulley: last four #'s 1105

Note: Rods: LT1 "pink" rods. 5.7", 6th design, forged steel, shot peened, magnafluxed, heat treated, high RPM rod bolts and expensive.
Intake 3972116 listed as service replacement manifold.

1971 Z28 Engine - LT1 330hp (gross, 275hp NET)
Casting # GM P/NDescription
Block3970010 4 bolt main, suffix codes: CGP, CGR
Crankshaft 330550Forged steel
Heads 3973487 75.47 cc, 2.02/1.6 valves, screw in studs & guide plates
Cam 3972182 3972178 symbol: (1) square Solid lifter - 0.458(I)/0.484(E) lift, 317I/346E duration
Pistons Flat w/valve relief - yields 9.0:1 compression
Intake 3959594
Carb (A/T) 3989022Holley List 4800, 780cfm , 4150 series - 4BBL
Carb (M/T) 3989021Holley List 4801, 780cfm , 4150 series - 4BBL
LH Exhaust 3989041 Rear exit, log type w/AIR, 2.026 outlet
RH Exhaust 3986330 Rear exit, log type w/AIR, 1.96 outlet
Distributor 1112049 Manual Trans, RFI, single point w/vacuum
Distributor 1112074 Auto Trans, RFI, single point w/vacuum
Alternator: Delcotron 37 Amp, part # 1100837
Water Pump: 3957170

Cylinder head has swirl polished valves and chrome valve stems.
Alternate cylinder head was 3986316 (unverified).

1972 Z28 Engine - LT1 255hp (net)
Casting # GM P/NDescription
Block3970010 4 bolt main, suffix codes: CKS, CKT
Crankshaft 330550Forged steel
Heads 3998916 76.18 cc, 2.02/1.6 valves, screw in studs & guide plates
Cam 3972182 3972178 symbol: (1) square Solid lifter - 0.458(I)/0.484(E) lift, 317I/346E duration
Pistons Flat w/valve relief - yields 9.0:1 compression
Intake 3959594
Carb (A/T) 3997788 GBHolley List 6238, 780cfm , 4150 series - 4BBL
Carb (M/T) 3999263 GAHolley List 6239, 780cfm , 4150 series - 4BBL
LH Exhaust 3989041 Rear exit, log type w/AIR, 2.026 outlet
RH Exhaust 3986330 Rear exit, log type w/AIR, 1.96 outlet
Distributor 1112095 Manual Trans, RFI, single point w/vacuum
Distributor 1112049 Auto Trans, RFI, single point w/vacuum
Distributor 1112153 2nd design - M/T, single point w/vacuum & ECC
Distributor 1112156 2nd design - A/T, single point w/vacuum & ECC
Alternator: Delcotron 37 Amp, part # 1102454
Water Pump: 6263701

unverified but alternate head casting #'s include: 3973487, 3973487X, & 3998993


Last updated: 10/20/2011
Author: MadMike Maciolek

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