66 C10 Carb question?

[Prflyer1]

I am somewhat clueless about Carbs, while cleaning the engine bay and engine I thought I had broken a line to the carb. I believe its the original Rochester Carb, the line in question in the picture was attached by a rubber type union or cover. Today when I got the engine ready I started and ran it for a while with absolutely nothing wrong, no gasoline coming out either side of the line. Is this some kind of breather line? or a line that was eliminated for some reason? any help will be appreciated, apologies for the bad pictures.

[TJ's Chevy]

From what I can see...that is your vacuum advance line. That line will go from the carb to the little pump on the distributor.

[Prflyer1]

Originally Posted by TJ's Chevy

From what I can see...that is your vacuum advance line. That line will go from the carb to the little pump on the distributor.

Yes, that is exactly where it goes, now pardon my complete ignorance, what does it do? and thanks in advance

[Prflyer1]

I googled it with the name you gave me and now understand, thanks!

It also has another deleted line...

[TJ's Chevy]

Originally Posted by Prflyer1

thanks in advance

You Nailed what is does! lol! It's your vacuum advance.

[j.kirn]

That is not the correct carb or factory carb you have there

[TJ's Chevy]

Originally Posted by j.kirn

That is not the correct carb or factory carb you have there

WRONG, the later model 250's and 292's came with monojets.

[j.kirn]

Originally Posted by TJ's Chevy

WRONG, the later model 250's and 292's came with monojets.

never seen a monojet on a 292 a 250 yes

[j.kirn]

Originally Posted by TJ's Chevy

WRONG, the later model 250's and 292's came with monojets.

according to info then this is not the factory correct carb for this truck as I said, later models engines yes but since he stated it is a 66 a monojet is not the correct carb

[TJ's Chevy]

Originally Posted by j.kirn

according to info then this is not the factory correct carb for this truck as I said, later models engines yes but since he stated it is a 66 a monojet is not the correct carb

Um, Why are you telling me this??? I was the one stating in the first place that these came with monojets in the LATER years. Had nothing to do weather it was Factory or not...it had to do with the fact you stated they were not Correct for these engines at all when...Yes...indeed they were for later years.

And to show that once again the "I've never seen one yet" knowledge is not a valid reason that they were not used.

If I could have a dollar from every person that sated, "I've never seen a GMC 305 v6 therefore they don't exist." I would be a millionaire!

[j.kirn]

Originally Posted by TJ's Chevy

Um, Why are you telling me this??? I was the one stating in the first place that these came with monojets in the LATER years. Had nothing to do weather it was Factory or not...it had to do with the fact you stated they were not Correct for these engines at all when...Yes...indeed they were for later years.

And to show that once again the "I've never seen one yet" knowledge is not a valid reason that they were not used.

If I could have a dollar from every person that sated, "I've never seen a GMC 305 v6 therefore they don't exist." I would be a millionaire!

you said wrong! correct factory carb would not be a monojet for a 66 inline, your statement is correct for later year but had nothing to do with my statement

[vince1]

I saw a carb just like that on a 67 or newer truck in the pick n pull yard. Definitely different from a stock 66 carb.

[vince1]

When my carb was off I measured its bore diameter at 1 9/16" The diameter in the manifold was 1 5/8". I think I read that 250's get 1 9/16" carbs and 292's get 1 5/8" carbs. Do they do the monojets the same way?

[TJ's Chevy]

Originally Posted by vince1

When my carb was off I measured its bore diameter at 1 9/16" The diameter in the manifold was 1 5/8". I think I read that 250's get 1 9/16" carbs and 292's get 1 5/8" carbs. Do they do the monojets the same way?

I'm not positive, but most likely yes they do.

[Wrenchbender Ret]

The Monojet came out in 1968. It worked for the new emission laws. 1976 on back had the Roch. model B. The MJ used on 292 engines did have a larger throat & venturie then the 250. Often they have been changed around as the rebuilders don't separate them.
That vacuum outlet might go to the modulator if it has an automatic trans. The dist vacuum was generally hooked to ported vacuum which has an outlet on the other side.