Hey Guys,

On my friend's 1970 440-4 Motor, I noticed that this vacuum hose at the back of the intake manifold is not hooked up to go anywhere (nor is the end plugged). The larger hose in the picture goes to the Power Brake Booster, but this one was just resting there on the intake manifold.

Anyone know what the purpose of this particular vacuum hose is and where it needs to go(or should be it plugged?).

Also, one related question -- would having this hose there unhooked like this, take performance away from the Power Brake Booster?

Thanks a lot guys for any tips!

-Stan

stock air cleaner? just a guess.. also, I don't think it would impact the brakes if it's not hooked up to anything.

Not connected it is a vacuum leak and can cause the engine to run lean. It may take some vacuum away from the brakes, just depends on how strong the signal was before and the inside diameter of the unconnected line.

The line probbably goes to the stock air cleaners thermostat control that closes the air cleaner door when cold.

Definitely remove the hose and cap off the port if it's not being used.

if you have a stock air cleaner, it would go to the vacuum switch mount in the base of the air cleaner. the other side of the vacuum switch goes to the vacuum actuator on the aircleaner snout to divert the carb air from the snout to the heated air intake manifold mounted on the exhaust manifold.

if you dont have that setup, just cap it off. a vacuum leak will hurt your vacuum signal to the carb and hurt your performance (youll run lean)

actually that seems more likely for heater or a/c vacuum.
Or at least you are missing that hose if it isn't there. Something has to go back into the passenger compartment for that system.

What year and body style is the engine in ?
I assume the engine isn't original to the car it's in

That nipple is for vacuum to an A/C switch, if the car doesn't have A/C but still has P.B. it should have a single large port style nipple...

it doesnt look long enough to reach anywhere close to where an ac vacuum switch would be.

Hi. Thanks guys for the tips.

This is in a '70 Challenger - 440 A/T car, but non-AC. I am not sure if this is the original motor for it, but I'll check out the VIN this weekend on it.

Thanks again.
--Stan

well it doesn't have to be an a/c car. My heater only car had one vacuum hose that went into the car for the vacuum actuated switch for defrost to heat.

The vacuum line should enter the firewall just below the blower motor on the passenger side. See my pic of my 71 roadrunner. The 70 Challenger should only have one hose entering the firewall since the heater valve is controlled by a sliding wire. The firewall layout should be similiar.
Ron