Original 6 pack experts

[ls1slow]

I recently bought a NOS vacuum carb choke pull off it looks in good condition the vacuum holds. It has a number 12 stamped on the side of it I can’t find any information if most these chokes had a number stamped into them. I’ve read the divorce chokes have the last 2 of the part number stamped into them but can’t find anything on the choke diagram. Then there’s a small spot of rust from sitting in the box is there any way to re plate these

 

[pnora]

I recently bought a NOS carb choke it looks in good condition the vacuum holds. It has a number 12 stamped on the side of it I can’t find any information if most these chokes had a number stamped into them. I’ve read the divorce chokes have the last 2 of the part number stamped into them but can’t find anything on the choke diagram. Then there’s a small spot of rust from sitting in the box is there any way to re plate these

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Just so you know that is not an actual choke. Its a vacuum break or pull off.

 

[ls1slow]

Thanks updated post as a vacuum pull off choke

 

[fastmark]

I restore six packs so here’s the skinny on these. That’s a 50 year old NOS part you have there and I bet it cost a pretty penny. Look at a couple of things. First the bent downward vacuum port is only found on original carbs. Secondly, the plating on the original carbs is different than what we can do now. The steel parts are much lighter than the yellow zinc we can do currently. The EPA outlawed the original chemicals long ago. It can be replaced but it will turn out much more yellow . Now the ones I get plated are used units that have to be taken apart, plated and the reassembled. The diaphragm won’t stand the plating and they very seldom work. I can tell the rebuilt/plated ones from oem, but most can’t unless I told you. All the ones you see on eBay that are readily available are rebuilt. Now they are 50 years old cores as well so many have imperfections. I try to cull the blemished ones when I buy the. I make a long drive to pick mine up. The eBay one are quite expensive. I furnish a new one when I restore a set of carbs.

I’ll start back up restoring carbs in a few months. I’m building a couple of motors for customers. Any more information and I’d have to kill you! This carb restoration business is kind of a secret society. Lol!

 

[fastmark]

Oh, I’ve seen lots of numbers on the pull off. I’ll look at my NOS one and the originals I have at the shop.

 

[fastmark]

Ok. Just looked at my stash. I’ve got a lot, too. My NOS 70 440 auto list 4376 and dated 3119 assembly line carb has a 12 stamped on it. My almost new 69 4391 dated 1989 carb was built after the initial run of cars and sold over the counter. It has a 94 on the choke pull off. That seems to be the rule with the ones I still have on the original carbs. I have to trade in my cores to be rebuilt and pick what I need when I buy them. This company disassembles many Holley choke pull offs and rebuilds them. The turn down vacuum port is the most desirable. Remember Holley manufactured a lot of carbs with pull offs. The later issue carbs were all straight and less desirable. I have very few still left on original carbs to tell 100% but I feel I’m close on this. The picture of the rebuilt choke pull off with the NOS carb is to compare the color. My plan is to do my own plating some day and I may be able to change that but for right now. This is all we’ve got.

 

[ls1slow]

Thanks @fastmark I got lucky and didn’t spend a whole lot on this but feel a lot better that it is a true nos part I wonder why they stamped a 12 on them since it doesn’t correspond to part number

 

[Floyd]

Here’s a pic from an original 1970 340-6 with a “94” stamp

 

[Floyd]

Here’s an NOS part with the yellow zinc - appearing plating.

 

[fastmark]

Floyd, I hate to tell you but that choke pull off is one just like mine. It’s been rebuilt. You have an NOS box and that’s all. I can point it out to you on the rebuilt one but I’ll have to show you on the original what is the difference. I’ll have to take a picture of both sides. When I point it out to you, it will be easy to tell. I hope you did not pay that much for the NOS one in the box. Chicago Corvette gets $54.95 on eBay for the rebuilt ones. I’m not going to tell you what they cost me.

 

[Floyd]

@fastmark Sure, I’d like to know the difference. I got the part years ago and can’t even remember what I paid. I’m not sweating it, in fact, I put it on my T/A this afternoon. I’m running new Holley’s on my Car (purchased back in 1999) and continue to learn about all the subtle differences between OE carbs and later over-the-counter parts.

 

[fastmark]

I’ll shoot a picture and post it later.

 

[fastmark]

I replied to this yesterday but I must have forgot to push the post button. So let’s try again.

So I don’t have to post my photos because the OP has the pictures I need. There are several ways to tell but the most obvious is how they are put together. The original pull offs, when they are made by Holley, are made in two pieces. If you look closely, you can see the crimped edge on the vacuum tube side of the original piece. The other side is all one piece. The rebuilt pull off is taken apart by removing the crimped edge by grinding it away, not just prying it up. Then, after all the parts are plated, it is reassembled with a new “ring”and new diaphragm. If you look closely on Floyd’s, you will notice it has an edge on both sides of the part. Also the original round rod is made out of brass and not plated on the originals. The rebuilds are plated that same bright color.

These units are made from a multitude of different pull off and not just ones sold oem on six packs in 69-71. They don’t specifically hunt and rebuild just and oem units. With certain numbers on the bracket. The cores are getting harder and harder to find for them. I guess I could make some requests of them but it might get complicated getting my original cores back with the correct numbers.

Don’t get me wrong, if it were not for this company rebuilding these, we would have run out of the dropped tubed version long ago and be using the straight version used on regular four barrels and later issue six packs. So, they are a needed service and do a great job on a part that has not been made in years.

I’m sure the guys that get the pull offs from the same place that I do, won’t like me spreading this speed secret around so let’s just don’t spread this around ,ok? Lol.so if I don’t come back to the site, you know I got bumped off by an another carb restoration guy!

 

[Floyd]

Mark, thanks for the explanation and education! That’s a pretty ingenious way they came up with to restore them.

 

[ls1slow]

I agree and I’m with mark least someone is saving these unique things. So we don’t have to use the straight vacuum port style. So glad these forums exist for knowledge like this.