How to Replace SBC Intake Manifold Gasket

The intake manifold of your vehicle is responsible for creating the proper mixture of fuel to air for combustion in your motor. Between the intake manifold and the engine block is a thin gasket that seals the motor to create an air tight chamber. This seal is under tremendous pressure and can sometimes fail as it ages. Although gasket failure is uncommon with the new synthetic materials, older gaskets were often made of cork or thin sheet metal and were a common problem.

Instructions

Remove the Intake Manifold

1

Disconnect the upper radiator hose from the manifold by releasing the clamp that secures the hose to the manifold. Depending on the year and make of the car, the hose may be clamped in place with a screw clamp or bot clamp.

2

Disconnect the heater and vacuum hoses from the manifold and mark their location and where they connect with tags or a marker. Some motors will have an engine hose diagram, but these diagrams are often corroded away on older vehicles.

3

Disconnect all the connections from the carburetor, including sensors, vacuum lines, fuel lines and throttle linkage. You will need to use a flat head screwdriver to remove the linkage, vacuum hoses and open ended wrenches for the fuel lines.

4

Remove the 12 manifold bolts that secure the intake to the engine block. These bolts are 9/16 inch or 1/2 inch depending on the year and make of the engine.

5

Use a flat head screwdriver to pry along the edges of the manifold. Work all the way around the manifold and check to make sure all the wires and hoses are disconnected. Pull of the manifold.

Install a New Gasket

6

Use the shop cloth to wipe down the intake ports on the motor and the ports on the manifold you removed. Be sure not to spill any debris into the motor because it can cause damage to the cylinder heads.

7

Apply RTV liquid gasket to one side of the new gasket and place it with the sealant against the motor. Apply sealant to the exposed side of the gasket also. Repeat the process on both sides.

8

Reinstall the manifold to the engine block and use the ratchet and sockets to reinstall the manifold bolts. Tighten the bolts down to the recommended manufacturer specifications, which for SBC manifold bolts is 25 ft. lbs.

9

Reattach the hoses, vacuum lines, sensors, throttle linkage and fuel lines to the carburetor and manifold. Be sure you match up the markings you made earlier. This is the most crucial part of the reinstallation. A crossed-up hose can cause the engine to malfunction and potentially cause engine damage.

10

Reconnect the radiator hose and tighten down the clamps with a flat head screwdriver. Refill the fluid from the bucket into the radiator. Double-check all the fittings and connections to make sure there are no loose ends in the engine bay.