What is this open tube coming off the front of my exhaust manifold

[Spaceman]

Appears to come straight off the front passenger side exhaust manifold. Turns a 90 degree bend upwards and then is just open to the engine bay.

 

[Sheriff41]

That is the heat shield and there is a flexible tube that connects it to the factory air cleaner. The system allowed air warmed by the exhaust manifold to enter the carburetor until the engine got to operating temperatures.

 

[Spaceman]

Thank you! Is it fine to leave as-is or should I cap it or something?

 

[Sheriff41]

You can just leave it since you're running an aftermarket air cleaner. You could remove it but don't throw it away!

 

[Big Red Mach 1]

That part is useless to you now, but they can go for decent money. Put it up in a box or sell it, but it's really just in the way on your car now.

 

[Stanglover]

DO NOT throw it away. You might decide to return the car to a more original state and replace the air cleaner or even add ram air.
Here's what it should look like.

EDIT: Ooops! I just realized he has a 302, probably should have checked first, but a similar set-up. Air cleaner will be different.

 

[Michael O’Harran]

That is the heat shield and there is a flexible tube that connects it to the factory air cleaner. The system allowed air warmed by the exhaust manifold to enter the carburetor until the engine got to operating temperatures.

Is it long or short? The length of the shield and in what condition?

 

[CrzyNickRatkllr]

Appears to come straight off the front passenger side exhaust manifold. Turns a 90 degree bend upwards and then is just open to the engine bay.

It's your heat riser for stock carb. As car warms up, it opens up your choke.

 

[Stanglover]

It's your heat riser for stock carb. As car warms up, it opens up your choke.

Your right, the heat riser draws warm air into the air cleaner and yes, it does help with choke operation. There is also a vacuum operated thermal switch that will open the snorkel air door once the set temp is reached and in tern, sealing off the heat riser so therefore drawing only cool air into the carb. This is one reason open aftermarket air cleaners can be troublesome in cool weather.