Stefano

7040256 W30 4 Speed Carb

Thoughts on stamp?

70-442-W30

I'm no expert on these, but here is mine if you need to compare:




I can go out and try to get a better pic if needed.

70-442-W30

ok, got it now...mine is the top pic and yours is the bottom pic. See below:

11971four4two

amazing how the font does not look the same

70-442-W30

It could have something to do with my lens. It is a 60x zoom camera so sometimes it does distort a bit. But the thing I notice most regardless of font, is the spacing between the 256 and the UA.

Stefano

IMHO since the W-30 carbs were built in batches, you need to compare to the batches as stamps could have varied in the timeline between the carbs.

jensenracing77

I am not the expert but I believe that is a restamp. Here is another known real one.

EDIT: it is hard to say but Sam would likely be the best to determine

66-3X2 442

I agree,it looks like a fake.

72xw30

IMO, it appears to be a restamp/fake.

A few things give it away as discussed before in the "restamped parts" thread.

Sam

jensenracing77

I would have to disagree a little. As I said in the restamp thread, Your best source of original stampings are from common number carburetors. I have a big pile of common number carburetors and it is amazing just how consistent the stamping are between 1968 and 1975.

marxjunk

on the first carb.....the 7s...the 4 the 5 and the A are wrong...

plus its a perfect stamp..i mean perfect and thats a warning sign

the more i look at it the 6 is wrong and so is the 2

you can see on the second carb the 256 is out of align in the part number.and thats the batch stamp trait, but the date is nice and straight..like most...

the 3rd carb has the same mis alignment on the 256..like a batch stamp would..

carb number 1 the part number is in the wrong spot too...its centered up kinda..the others, the part number is closer to the base plate.

first carb seems like a restamp to me..

70Post

What I see is a distinct lack of "grain/texture" on the surface where the Stefano-pic'd carb is stamped. This surface was NOT machined prior to stamping by Rochester, etc. Look at other "as cast" surfaces on the carbs in the various pics....they have all sorts of minor imperfections, "pits", etc in the cast surface (ie - the unique "grain" or texture I refer to).

If you look at the cast surfaces on other parts of the Stefano-pic'd carb you can see they exhibit plenty of the "as cast" grain/texture.

Let your eyes roam from the plane/surface where the stamping is to other parts/surfaces and NOTICE.....ah yes!! GRAIN and TEXTURE suddenly reappear!

The carb Stefano shows is VERY smooth on the stamping surface area with no grain, imperfections, etc. Machined and then smoothed to remove machining evidence and or sharp edges? Filled over with a zinc type welding rod and then smoothed, etc?? They left out the last part....making the surface look REAL, IMO.

EDIT AND ADD: it may be nothing but immediately above the "7040256" number there is a raised "pad" that is oriented perpendicular to the stamping area.....look at the lower L hand corner of this raised pad (above the "2" in the "7040356" number).....almost looks like a grinder/sander cut into the raised pad where it meets the stamping surface plane. Look at the other pics posted....none of them show this "irregularity". Checked 3 Rochesters here (2 '70 carbs and a '71) and all are perfect in that area. My bet is someone "slipped" a bit when grinding/sanding. That may be where the edge of a file, sanding pad, etc cut into that lower corner.

And...it may be the pic but this "ground into" area seems to subtly extend all the way down the pad at its base.....seems like a slight "valley" along the bottom of that pad....again, from machining/grinding. Not evident in any of the other carb pics posted.

The harder they "try" the worse they fail.

Now you can entertain yourself with the litany of "excuses" the seller will come up with when questioned....

>"Rochester sometimes had to "pre smooth" the stamping surface because they REALLY wanted that area to be clean for a good stamping" (Try and hold back your laughter at this point).

>"At some point Rochester worked on the tooling and molds to "remedy" the stamping "pad" inconsistency problem so this area, post-remedy, always appears much cleaner/smoother than prior carbs" (OK--now you can cough a little this time while muttering "bulls#*" under your breathe....remain silent as there will be more fun "excuses" in response to your silence)

>"Hey, I was TOLD, by a real knowledgeable guy that he's seen this on MANY Rochester carbs over the years.....you know, these things weren't manufactured in clean rooms like the semiconductor plants of today and there were always some REAL inconsistencies in the castings!!!!"

>"I'm just trying to sell some nice parts man....."

>"Dude, who are you??!! Were you AT ROCHESTER when these were made?? No?? Then who are you to tell me that this is a fake!!?????"

OK - that's just me "talking".....now I'll be embarrassed when it's proven it is real but it won't bug me a bit.

RetroRanger

possible evidence of machining ?

Joffroi

Again, no expert, but that font looks completely different. And the two little screws RetroRanger posted when the other examples don't have them. Shady.

rob1960

We all know that the '70 "256" & the '70 "255" carbs did not use primary power pistons or metering rods. Pull the airhorn & look inside. If I remember correctly the hole for the power piston to fit in isn't there on a true 255 or 256 carb, Also the staked in plug in the throttle base plate(right under the fuel inlet)for the factory power piston setting isn't there either,it wasn't needed,it was just a smooth casting on the front. I posted a pic of my '68 carb & you can see the plug that's in all the regular q-jets. It's been since the mid '70s since I had one of these original carbs apart but those 2 things stood out. Maybe you guys that still have originals could verify this for Stefano & the rest of us.

70-442-W30

Here is a close up with my iphone, so there should be no distortion like there possibly was with my zoom lens camera:

joe_padavano

Am I the only one bothered by the fact that the main body, where the stamp is located, appears to have been recolored, but the air horn still shows signs of corrosion in this photo? Seems to me, as they say about botox and implants, she seems to have had some work done...

Stefano

W-30 4 Speed Carb

joe_padavano

Yup. Clearly a different font.

Stefano

I do have to say that, ya'll make for some good forensics carb checkers.

Now what to do about the guys making them.....tar & feathers?

Thanks for the comments.

70-442-W30

That looks a lot more like the one I have. The triangle in the "A" is larger and also the year is dropped lower a bit like mine also. Spacing also matches between the part # and the UA. So if I were to pick one I would most likely drop some money on, I would pick the one you just posted.

joe_padavano

Didn't we just do that?

Virtually, anyway.

11971four4two

these days the MFg seems to get off fine
LoL


If you sell bogus ****
you must pay pack
buyer and sundry

RocketDevo

Sorry Stefano, it is a fake. As many have already pointed out its various short comings, there are other sign's. To the right side of the part number where the body of the carb meets the gasket there is a raised ridge left over from casting. It is missing on said carb, confirming the surface has been altered (sanded). This compliments what others have said about grinding or sanding marks being visible. The two letter assembly plant code is almost never a deep stamp on any Rochester carb, and the difference can be seen in the other photo's posted. The "5" should sit just above the "2" if you were to continue a line from the bottom of the "2". What is peculiar on original 256 carburetor's, the "6" sits back lower than the "5". This is unique among the 7040256 carburetors, as generally the last two numbers sit even with each other.
Finally as rob1960 touch on, the 255 and 256 do not have the APT plug on the aluminum base plate.

Dave Siltman

I have a known restamp of this exact numbered carb. Yes, I knew it was a restamp when I bought it, but it is a rebuilt, rebushed, redyed-recolored, bench flowed, carb. It is a mule that I use and it works flawlessly. It was done by a very well known rebuilder, but HE DID NOT RESTAMP IT AND HIS NAME WILL NOT BE ASSOCIATED WITH IT IN ANY WAY. I can provide pics of the numbers on that carb if anyone is interested.

Stefano

I got mine from a Guy, who bought it from a prior member on this site. He also purchased other items which were purported to be real but turned out to be restamps. These criminals are still out there preying on the uniformed.

AzMotorhead

Rob. The bore is there for the power piston and primary needle hanger.
Though its not drilled at the bottom so vacuum can be ported to its bottom side.
I sent my 256 carb off to a credible national rebuilder(supposed experts)
It came back looking good but wouldn't run worth a crap. I took the top off and they had stuck a power piston and needles in it.
No they (piston & needles) didnt work but were in there none the less.
Also note the primary jets have a different shape to their bore taper . Not just any old jet will work properly

rob1960

Thanks for jogging the old memory banks Joe!! I do remember the 256 carb on my buddies W30 having the small cup plug in the power piston bore.

70-442-W30

When I ordered a choke pull off for my carb, they were showing a 256 carb for $300. Had this disclaimer: "This Rebuild will look and perform like the original but will NOT have ref Carb number on it"

Octania

I believe the factory simply used 2-bbl jets in that hole.

rob1960

Yes, they were just 2bbl jets in the front. The W31 "255" came with 57 jets,the W30 "256" came with 58s. The std Q-jets with the metering rods used 69 or 70 jets depending on the application in '70

anthonyP

What was the outcome of the stamped pin dots seen before the part number, was it ever determined that they indicate the carburetor is a service or re-stamp? Are the last three numbers always the same fonts, size, and level with the beginning part numbers, or are they usually different? Does anyone have an opinion on this carburetor's stamping:

https://classicoldsmobile.com/forums...5-4-speed.html

RocketDevo

The 07040253 from the link you provided I do not believe is real. The first zero is not standard practise to be stamped. I have seen the pin dots before, but I am not 100% positive they definitively indicate a re-stamp. I will say they majority of carbs do not have them, and thus there should be no need for them. The prefix numbers are stamped first, then after the carb is completed, it receives its 2 final number corresponding designation. The final 2 numbers are not usually level with the prefix numbers. If you look at the numbers and the way they are stamped. you can see the changes. the 0704 was stamped at the same time, then the next zero, then the "2 5" and then the final "3". A factory original would never be stamped that way. The final "3" is brutal. The most plausible explanation is that it has been re-stamped, or the guy was on something the day he stamped it. The photo is a NOS 253 carb, albeit 71 model year for comparison.

anthonyP

Thank you very much RocketDevo for the information on the 7040253 carburetor. Like when looking at a very good forged bill, having an authentic one for comparison makes a world of difference. I will keep looking for a stick carburetor for my '70 442 even though the later model automatic carburetor on the car operates okay.

Stefano

Here is one which has been on the car for at least 20 years.

anthonyP

Thanks Stefano. You can clearly see the casting part number differences between this one and the one for sale. Hopefully one like this can be found at a reasonable price.

Koda

It's time to go cut some nuts! That's a fake, and fakers need the pain.

RetroRanger

I don't entirely agree. I think it's more likely a service replacement than a re stamp. Why would a re stamper go out out of her way to make it obvious it's a re stamp? Doesn't make sense, if she was trying to pass it off as original they wouldn't add obvious flags IMHO. I'm no expert so I would guess it's either a service replacement or maybe it was sourced as needed or for line failure or something.

Most re stamps that have been outed have had features such as replated, ground areas, ghost stamp, perfect lined up stamps w near perfect depth on all characters, that carb has none of those features the stamp looks like it was done by someone who could give 2 shots other than it need a stamp.

Stefano

The flat top "3" and the round "3" are different characters.

davebw31

The air horn for w31 and w30 used the same Rochester Part Number and the number is different than other carb applications for 1968-72'. I believe it has something to do with the secondary air valve to provide a "diffused" air flow and redirect the flow of that air when the secondary is staring to open. It was to distribute fuel out of the secondary circuit and main well at WOT more efficiently. It also had something to do with there being no power valve/metering rods for the primary jet circuit. I suggest checking the air horn number on a known legit w-carb verses a non-w carb. The Rochester number is under the air horn near the hole for the shaft of the accelerator pump and is circular. I know I have the part number, however only god knows where it is at!