Headers and carb connections?
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Headers and carb connections?
I have a 76 F250 Highboy w/ the 360. It has an Autolite 2bbl carb. This weekend I swapped the original exhaust manifolds for a set of Hedman Headers. There was one tube from the original manifolds to the carb for the choke so I put on a manual choke to eliminate this problem. There was an adapter for the stock air cleaner assembly, I eliminated the air cleaner with a K&N setup.
My question lies with the remaining tube that was on the manifolds. It was right next to the choke tube and ran to the bottom of the carb. Can I just cap it off? Whats it for? truck seems to run fine with out it.
Thanks.
My question lies with the remaining tube that was on the manifolds. It was right next to the choke tube and ran to the bottom of the carb. Can I just cap it off? Whats it for? truck seems to run fine with out it.
Thanks.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
I would plug it and see how it runs.
It should be plain engine vacuum (I think) that runs from the carb to the choke, and then to the exhaust manifold. As the manifold heats up, the air going into the choke warms up the choke which turns it off.
The problem is, I don't remember if that vacuum is on all the time (I think it is, otherwise the choke would eventually turn back on as it cools off). If that vacuum is on all the time, it's an "expected" vacuum leak like the PCV.
If you plug it, the carb will run just a slight bit richer. Your idle might drop a little bit too. I don't think it's enough to give a darn about though, so try it.
It should be plain engine vacuum (I think) that runs from the carb to the choke, and then to the exhaust manifold. As the manifold heats up, the air going into the choke warms up the choke which turns it off.
The problem is, I don't remember if that vacuum is on all the time (I think it is, otherwise the choke would eventually turn back on as it cools off). If that vacuum is on all the time, it's an "expected" vacuum leak like the PCV.
If you plug it, the carb will run just a slight bit richer. Your idle might drop a little bit too. I don't think it's enough to give a darn about though, so try it.
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