Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

SYS.OK|MANUAL.DB● LIVE

HOMESERVICE MANUALSCHEVROLET1966BISCAYNE 7.0L ENG, AUTOMATIC TRANS, TRANS MFR CD THM400REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEFUEL DELIVERYROCHESTER 4 MC & 4MV 4-BARRELDESCRIPTIONOLDSMOBILE "CLIMATIC COMBUSTION CONTROL"

1966 Chevrolet Biscayne 7.0L Eng, Automatic Trans, Trans Mfr CD THM400

Oldsmobile "Climatic Combustion Control"

1966 Chevrolet Biscayne 7.0L Eng, Automatic Trans, Trans Mfr CD THM400SECTION Oldsmobile "Climatic Combustion Control"

This device consists of a thermostatically controlled heated air inlet in the air cleaner (heated air drawn from stove on right hand exhaust pipe) which provides carburetor air temperature of 100°F when underhood temperature is less than 100°F.

Fig 1: 4MV IDLE AIR BLEED LOCATIONS

Courtesy of GENERAL MOTORS COMPANY

1965-66 CARBURETOR ADJUSTMENT SPECIFICATIONS (Table No. 1)

Rochester Carb. No.

Slow Idle Speed (Engine RPM)⁽¹⁾

Fast Idle Speed (Eng. RPM)

Float Level Setting

Pump Rod Setting

Idle Vent Setting

Air Valve Setting

Synchro-mesh

Auto. Trans.

7025200

..........

⁽²⁾

2000⁽⁷⁾

3/16"

9/32" ⁽⁸⁾

13/32"

1 1/16"

7025201

450-550

..........

2000⁽⁷⁾

3/16"

9/32" ⁽⁸⁾

13/32"

1 1/16"

7025220

..........

⁽²⁾

2000⁽⁷⁾

3/16"

9/32" ⁽⁸⁾

13/32"

1 1/16"

7025221

450-500

..........

2000⁽⁷⁾

3/16"

9/32" ⁽⁸⁾

13/32"

1 1/16"

7026200

..........

450-500 ⁽²⁾

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7026201

450-500

..........

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7026202

..........

450-500 ⁽²⁾

2200⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026203

450-500

..........

2200⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026204

..........

500-600 ⁽²⁾

2000⁽⁷⁾

1/4"

9/32"⁽⁸⁾

3/8"

1 1/4"

7026205

500-600

..........

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7026206

..........

500-600 ⁽⁴⁾

2000⁽⁶⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7026207

500-600

..........

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7026240

..........

500⁽⁴⁾

600 ⁽⁶⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 3/16"

7026242

..........

500⁽⁴⁾

600 ⁽⁶⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 3/16"

7026250

⁽⁹⁾

⁽¹⁰⁾

700 ⁽⁶⁾

11/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026254

600⁽³⁾

500⁽⁵⁾

700 ⁽⁶⁾

1 1/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026255

..........

550

700⁽⁶⁾

11/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026256

..........

550

700⁽⁶⁾

11/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026260

..........

500⁽³⁾

..........

7/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7026261

600⁽³⁾

..........

7/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7036200

..........

450-500 ⁽²⁾

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7036201

450-550

..........

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7036202

..........

600⁽³⁾

2200⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7036203

700⁽³⁾

..........

2200⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7036204

..........

550

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7036205

600

..........

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7036206

..........

550

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7036207

550

..........

2000⁽⁷⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 1/4"

7036240

..........

550⁽³⁾

600⁽⁶⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 3/16"

7036242

..........

550⁽³⁾

600⁽⁶⁾

1/4"

9/32" ⁽⁸⁾

3/8"

1 3/16"

7036250

⁽⁹⁾

⁽¹⁰⁾

700⁽⁶⁾

11/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

7036254

600⁽³⁾

700⁽⁶⁾

11/32"

9/32" ⁽⁸⁾

3/8"

1 1/8"

⁽¹⁾	Auto. Trans. in Drive. Air. Conditioner ON (Except as noted).

⁽²⁾	Set as low as possible for smooth idling in Drive to prevent creep and harsh shifts in service.

⁽³⁾	Air Conditioner OFF.

⁽⁴⁾	550 RPM on Air Cond. cars (Air Cond. OFF).

⁽⁵⁾	575 RPM on Air Cond. cars (Air Cond. OFF).

⁽⁶⁾	Cam follower on LOW step of fast idle cam.

⁽⁷⁾	Cam follower on HIGH step of fast idle cam.

⁽⁸⁾	Pump rod in INNER hole of pump lever.

⁽⁹⁾	600 RPM (400" Eng.), 550 RPM (425" Eng.) Air Conditioner OFF.

⁽¹⁰⁾	600 RPM (400" Eng.), 500 RPM (425" Eng. without Air Cond.), 575 RPM (425" Eng. with Air Cond.). Air Conditioner OFF.

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready Tools Free Quote Check Quote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.

Safety Warning

Oldsmobile &quot;Climatic Combustion Control&quot;

Use the Manual With the Right Hardware

When to See a Mechanic

Oldsmobile "Climatic Combustion Control"