1968 AMA Specifications – Engine

AMA Specifications-Passenger Car
— Engine —

MODEL

Firebird

Firebird Sprint

Firebird 350

Firebird H.O.

Firebird 400

Engine – General

Type, no. cyls., valve arr.

Line, 6, Overhead Cam

90 degree V. 8, In-Head

Bore and stroke (nominal)

3.8750    3.525

x

3.8774    3.535

3.8750    3.746

x

3.8774    3.754

4.1200    3.746

x

4.1224    3.754

Piston displcement, cu. in.

250

350

400

Bore spacing

4.4

4.62

No. System (front to rear)

L. Bank

1-2-3-4-5-6 (In-Line)

1-3-5-7

R. Bank

—-

2-4-6-8

Firing Order

1-5-3-6-2-4

1-8-4-3-6-5-7-2

Compres. ratio (nominal)

9.0:1

10.5:1

9.2:1

10.5:1

10.75:1

Cylinder Head Material

Alloy Cast Iron

Cylinder Block Material

Alloy Cast Iron

Cyl. Sleeve-Wet, dry, none

None

Number of mfg. points

Front

2

Rear

1

Engine installation angle

3° 35´

Taxable horsepower

Dia>^² x No. Cyl.

2.5

36.0

48.0

54.3

Publishing max. bhp*@eng. RPM

175@4800

215@5200

265@4600

320@5100

330@4800

Publishing max. torque*lb. ft. @eng. RPM

240@2600

255@3800

355@2800

380@3200

430@3300

Recommended fuel regular – premium

Regular

Premium

Rugular

Premium

Premium

Engine – Pistons

Material

Aluminum Alloy

Description and finish

Cam Ground Slipper Type – Tin Plated

Weight (piston only) oz.

19.740 – 19.920

21.010 – 21.190

22.070 – 22.2

Clearance (limits)

Top land

0.024 – 0.029

0.017 – 0.02

Skirt Top

0.0022 – 0.0028 (a)

0.0025 – 0.0031

Skirt Bottom

0.0017 – 0.0033

0.0020 – 0.003

Weight (piston only) oz.

19.740 – 19.920

21.010 – 21.190

22.070 – 22.2

Ring groove depth

No. 1 ring

3.427 – 3.437

3.667 – 3.67

No. 2 ring

3.427 – 3.437

3.667 – 3.67

No. 3 ring

3.446 – 3.456

3.670 -3.68

No. 4 ring

None

(a) Pistons selected for clearance at 1.110 below top of piston.

MODEL

Firebird 250 cu. in. Engines

Firebird 350 cu. in. Engines

Firebird 400 cu. in. Engines

Engine – Rings

Function (top to bottom)

No. 1, oil or comp.

Compression

No. 2, oil or comp.

Compression

No. 3, oil or comp.

Oil

No. 4, oil or comp.

None

Compression

Description – material, coating, etc.

Cast Iron Reverse Twist With –

(a) or (b)

(c) or #1 and #2 Taper Face Moly Channel

#1 and #2 Taper Face Moly Channel

Width

0.0778

No. 1 0.0778 No. 2 0.0775

Gap

0.015

0.19

Oil

Description – material, coating, etc.

Multi-Piece (2 Rails and 1 Expander)

Rails: Steel with Chrome Plated O. D.

Expander: Stainless Steel

Width

0.186

Gap

0.035

Expanders

In Oil Ring Assembly

Engine – Piston Pins

Material

SAE 5015

SAE 1016

Length

3.00

3.25

Diameter

0.9272

0.9802

Type

Locked in rod, inpiston, floating, etc.

Locked in Rod

Busing – In rod or piston

None

Busing – Material

None

Clearance

In piston

0.0003 – 0.0005

0.0005 – 0.0007

In rod

Press Fit

Direction and amount offset in piston

To Right – 0.063

Engine – Connecting Rods

Material

SAE 1037, 1038 or 1141

Arma Steel

Weight (oz.)

23.9

31.7

Length (center to center)

5.70

6.625

Bearing

Material and Type

Moraine 100-A (d)(e)(f)

Moraine400-A (d)

Overall Length

0.837

0.88

Clearance (limits)

0.0007 – 0.0027 (g)

0.0005 – 0.0025

0.0005 – 0.0026

End play

0.0085 – 0.0135

0.006 – 0.011 (Total for Two)

(a) 250 1 bbl. Engine: #1 – Barrel Face Moly Channel, #2 – Barrel Face Tin Plated

(b) 250 4 bbl. Engine: #1 – Barrel Face Moly Channel, #2 – Taper Face Moly Channel

(c) 350 2 bbl. Engine: #1 – Taper Face Moly Channel, #2 – Taper Face Tin Plated

(d) Steel backed removable precision

(e) Moraine 400-A on 4 bbl. 250 cu. in. engines

(f) Moraine 400-A on 4 bbl. 350 cu. in. engines

(g) 0.0007 – 0.0028 on 4 bbl. 250 cu. in. engines

MODEL

Firebird 250 cu. in. Engines

Firebird 350 cu. in. Engines

Firebird 400 cu. in. Engines

Engine – Crankshaft

Material

Nodular Iron (d)

Vibration damper type

Rubber Floated Weight

End thrust taken by bearing (No.)

7

4

Crankshaft end play

0.002 – 0.006

0.0035 – 0.0085

Main bearing

Material and type

Durex 100-A* Steel Backed, Removable, Precision (b)

Clearance

0.0003 – 0.0019

0.0002 – 0.0017 (c)

Journal

dia. and

bearing

overall

length

No. 1

2.30 x 0.80

3.00 x 0.94

No. 2

2.30 x 0.80

3.00 x 0.94

No. 3

2.30 x 0.80

3.00 x 0.94

No. 4

2.30 x 0.80

3.00 x 1.13

No. 5

2.30 x 0.80

3.00 x 1.59

No. 6

2.30 x 0.80

None

No. 7

2.30 x 1.01

None

Dir. and amt. cyl. offset

None

Crankpin journal diameter

2.00

2.25

*M-400 in lower half of No. 1,2,3, and 4 locations of 4 bbl. 450 cu. in. and 400 cu. in.

(a) Neoprene with fibre glass cord reinforcement

(b) M-400 in all locations of option 6 cylinder 4 bbl. engine

(c) 0.0012 – 0.0028 on Ram Air II Engine option

(d) Arma Steel on Ram Air II engine option

Engine – Camshaft

Location

Overhead

Between Cylinder Banks

Material

Hardened Alloy Cast Iron

Bearings

Material

Aluminum Alloy

Hight Lead Baffit on Steel

Number

7

5

Type of Drive

Gear or chain

Belt (a)

Chain

Crankshaft gear or sprocket material

Hardened Cast Iron

Carburized and Hardened Steel

Camshaft gear orsprocket material

Hardened Cast Iron

Aluminum Alloy with Nylon Covered

Timing Chain

No. of links

98 Teeth

60

Width

1.031 – 0.954

0.88 (Morse) – 1.00 (Link be)

Pitch

0.500

0.375

(a) Neoprene with fibreglass cord reinforcement

Engine – Valve System

Hydraulic lifters (Std., opt, NA

Standard

Valves rotator, type (intake, exhaust)

None

Rocker ratio

1.5:1

Operating

tappet

clearance

(indicate hot or cold)

Intake

0

Exhaust

0

MODEL

Firebird

Firebird Sprint

Firebird 350

Firebird H.O.

Firebird 400

Engine – Lubrication System

Type of lubrication (splash,pressure,nozzle

Main bearings

Pressure

Connecting rods

Pressure

Piston pins

Splash

Camshaft bearings

Pressure

Tappets

Pressure

Timing gear or chain

Metered Jet

Cylinder walls

Metered Jet

Oil pump type

Spur Gear

Normal oil pressure (lb. engine rpm)

26 – 36 # 2800 RPM

30 – 40 above 2600 RPM

55 – 60 above 2600 RPM

Oil press. sending unit (elect. or mech.)

Electric

Type oil intake (floating, stationary)

Stationary Screen

Oil filter system (full flow, part., other)

Full Flow

Filter replacement (element, complete)

Complete

Capacity of c case, less filter-refill (qt.)

5

Oil grade recommended (SAE viscosity and temperature range)

Anticipated Lowest Temp.

Single Viscosity

SAE Number

Acceptable

Alternate

Above Freezing (+32°F.)

20 W

10W – 30

Below Freezing (+0°F. to +32°F.)

10 W

10W – 30

Below Zero

5 W

5W – 20

Engine Service Reqmt. (MM, MS, etc)

MS

Engine – Exhaust System

TYPE (single, single with cross-over, dual, other)

Single (a)

Dual

Muffler No. and type (reverse flow, straight thru, separate resonator

One – Reverse Flow

(b)

One – Reverse Crossflow with Dual Inlets and Outlets (g)

Exhaust pipe dia.(O.D., wall thick.)

Branch

None (c)

2.00 x 0.060

None

Not Used

Main

2.00 x 0.060

2.25 x (d)

2.25 x 0.070

2.25 x 0.060

Front: 2.00 x 0.060 (h) Rear 2.25 x 0.070

Tail pipe dia. (O.D. and wall thickness)

Muffler Outlet Spout (or Spouts) 2.00 x 0.060

2.00 x 0.060 Muffler Outlet Spouts

(a) Dual system standard on H.O., Y pipe joins dual outlet manifold to single exhaust pipe on Sprint, Crossover pipe used on 350.

(b) One crossflow muffler with dual inlets and outlets, reverse flow resonator ahead of muffler in each pipe on dual systems.

(c) Sprint Y pipe legs 2.00 x 0.060.

(d) 0.076 – front section, 0.070 – rear section.

(e) Front section, 2.25 x 0.070 rear section.

(f) Except 350 HO engine which is same as Firebird 400 H.O.

(g) Reverse flow resonator ahead of muffler in each pipe.

(h) 2.25 x 0.076 with H.O. and Ram Air IV options.

Engine – Crankcase Ventilation System

Type (ventilates to atmos., induction system, other)

Standard

Induction System

Optional

None

Control Unit

Make and model

AC Type CV-735C

AC Type CV-679C

Location

Intake Manifold

Push Rod Cover

Energy source (manifold vacuum, carburetor air stream, other)

Manifold Vacuum

Control method (variable orifice, fixed orifice, other)

Variable Orifice

Complete system

Discharges (to intake manifold, carb. air intake, air cleaner intake, other)

Intake Manifold

Air inlet (breather cap, carburetor air cleaner, other)

Through Filter in the Carburetor Air Cleaner

Flame arrestor (screen, check valve, other)

Check Valve

MODEL

Firebird

Firebird Sprint

Firebird 350

Firebird H.O.

Firebird 400

Engine – Fuel System

6 Cyl. Engines

V-8 Engines

Induction type: Carburetor, fuel injection, supercharger.

Carburetor

FuelTank

Refill capacity (U.S. gals.)

18.5

Filler location

Center Rear

Fuel Pump

Type (elec. or mech.)

Mechanical

Locations

Right Front of Engine

Left Front of Engine

Pressure range

4.0 – 5.5

5.0 – 6.5

Vacuum booster (std., optional, none)

None

Fuel Filter

Type

Plastic Fabric in Fuel Tank and Sintered

Locations

Bronze in Carburetor Inlet (a)

Carbure-tor

Choke Type

Automatic

Intake manifold heat control (exhaust or water)

Exhaust

Air cleanertype (d)

Standard

Air Wetted Paper

Optional

Two Stage – Wetted Plastic Foam Over Paper Element

Idle speed (spec.neutral or drive)

N.      D.

Manual   N.

700

800

700

850

850*

Automatic D.

600

600

600

650

650*

Idle A F mix.

(a) Pleated paper instead of sintered bronze in the 1-bble. carb. for manual transmissions and all 4-bbl. carburetors.

**1000 With Ram Air Option

Engine – Cooling System

Type system (pressure, pressure vented, atmospheric, other)

Pressure Vented

Radiator cap relief valve pressure

14-17 P.S.I.

Circulation thermostat

Type (choke, bypass)

Choke

Starts to open at (°F)

190°

Water Pump

Type (centrifugal, other)

Centrifugal

GPM 1000 pump rpm

16

17

Number of pumps

One

Drive (V-belt, other)

V-Belt

Bearing type

Sealed Ball Bearing

Bypass recirculation type (inter., ext.)

External

Integral

Radiator core type (cellular, tube and fin, other)

Tube and Center

Cooling system capacity

With heater (qt.)

12.1

18.6(350)

17.8 (400)

Without heater (qt.)

Heater Standard Equipment

Opt. equipment-specify (qt.)

12.7 w/Air Cond.

20.2 (350), 19.4 (400) with A/C

Water jackets full length of cyl. (yes,no)

Yes

Water all around cylinder (yes,no)

Yes

Radiator hose

Lower

Number and type (molded, straight)

One, Molded

Inside diameter

1.75

Upper

Number and type (molded, straight)

One, Molded

Inside diameter

1.50

By-pass

Number and type (molded, straight)

One – External

One – Internal

Inside diameter

5/16

Hose Not Used

Fan

Number of blades and spacing

4 – 76° & 104° (a) (b)

Diameter

17.62

19.0

Ratio-fan to crankshaft rev.

.95:1 (1.08:1 with A/C)

.91:1(1.25:1 with A/C

Fan cutout type

Fluid Clutch-Thermostatically Controlled V-8 (A/C Only)

Bearing type

See Water Pump

*Drivebelts (indicatebelt usedby letter

Fan

A

|

A,B

|

A,C

|

B,C

A

|

A,B

|

A

|

B,D

A

|

A,B

|

A,C

|

B,C

 

|

B

|

 

|

B,D

 

|

 

|

C

|

C

E

|

F,G

|

E

|

F,I

|

E

|

F

|

E

|

F

|

E

|

F,G

|

E

|

F,I

|

 

|

G

|

 

|

I

|

 

|

 

|

H

|

H

|

Generator-alternator

Water pump

Power Steering

Air Conditioning

NOTES

(a) 7 blade 18 dia. PoWer-Flex fan on 6 cyl. with A/C.

(b) 7 blade 19.5 dia. fan on all V-8 with A/C – 5 blade 19 dia. Power-Flex std. on 400 V-8 except std. 4 blade fan used with Ram Air Option.

Drive Belt Dimensions

* Drive Belt Dimensions

A

B

C

D

E

F

G

H

I

J

K

Angle of V

36°

36°

36°

36°

36°

36°

36°

36°

36°

  

  

Nominal Length (SAE)

39.0

51.5

58.0

27.6

54.0

50.0

52.0

59.0

53.5

   

   

Width

.38

.47

.47

.38

.38

.38

.47

.47

.47

   

   

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