01-16-2015, 05:44 PM | #1 |
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What is this?
hey guys, I've been wondering for a while, what this is. It's a little hole and I can stick a pencil in it. The carb is a Rochester, mv1 I think. 72 250 custom/10. What are these things?
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01-16-2015, 05:54 PM | #2 |
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Re: What is this?
What ever you do, don't stick anything in it! j/k
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01-16-2015, 05:55 PM | #3 |
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Re: What is this?
It's obviously a # 2 pencil holder
no but seriously...I don't know...looking forward to finding out
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01-16-2015, 05:56 PM | #4 |
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Re: What is this?
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01-16-2015, 05:57 PM | #5 |
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Re: What is this?
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01-16-2015, 06:02 PM | #6 |
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Re: What is this?
does your truck have smog? maybe it has something to do with that but i dont think it filters out lead!!
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01-16-2015, 06:08 PM | #7 |
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Re: What is this?
If by smog you mean evap then yes it did but it didn't connect there, I have it unhooked now and it's basically just a vent for my gas tank. I dunno what smog is.
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01-16-2015, 06:09 PM | #8 |
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Re: What is this?
Every Rochester 1bbl I've seen has them. Here's a pic of a 74 with a little tube in it
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01-16-2015, 10:14 PM | #9 |
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Re: What is this?
Looks like a PVC port. Is the hole blind (dead ended), or does it lead into the throttle body? Is it pulling any vacuum when engine is running?
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01-16-2015, 10:21 PM | #10 |
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Re: What is this?
Yea it's dead ended. Does look like a PVC port but it's not, those are in a different spot on these models but good guess. I'm wondering if maybe it has something to do with a smog pump as he stated earlier. I do not have a smog pump.
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01-16-2015, 10:23 PM | #11 |
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Re: What is this?
Maybe we'll just say it's a pencil sharpener and leave it at that.
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01-17-2015, 12:28 AM | #12 |
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Re: What is this?
I believe it is a casting hole for a tube that might be used for another application. They used those carbs on more than just the chevy trucks. it would either be that or a cross drill port. usually they have plugs or pressed steel balls in them.
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01-17-2015, 12:49 AM | #13 |
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Re: What is this?
It is a bowl vent for the carb. It used to go to the evap. canister when the system was in place.
Just cap. No harm. No fowl.
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01-17-2015, 12:49 AM | #14 |
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Re: What is this?
Thanks for the info, I wonder what they were used for. Nice sig lol, reminds me of the shirts we sell at school that say " welders do it in all positions". Why are welders such pervs haha.
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01-17-2015, 12:50 AM | #15 |
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Re: What is this?
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01-17-2015, 08:34 AM | #16 |
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Re: What is this?
I'll guess. I know from looking that a '72 1bbl is one year-only. It's my guess that '72 was the first year of the new casting. It has the PVC port designed into the carb but left it blank in '72 and continued using the PVC port location from prior years
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