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I just want find out what this is obviously it’s some kind of adjustment ..my 70 does not have this and it’s advertised as a 70 and the numbers match up … maybe it’s a Cali thing who knows
Wow!
That is most unusual.
Any chance you have a picture from the throttle side?
I am just guessing mind you, but it looks like it goes directly into the spot where a throttle screw is on a Qjet.
And it does have a screw head.
So maybe some sort of idle speed screw extension?
But the round "cylinder" or "sphere" has me the most puzzled.
The "sphere" looks completely sealed, could it be some sort of automatic altitude adjustment via air pressure?
From: At my Bar drinking and wrenching in Lafayette Colorado
That's the stock, standard 1969-70 idle return damper which prevents sudden closing of the throttle on a 4-speed car to reduce emissions. It was used in place of the idle speed screw. It was commonly referred to as the idle speed "dashpot." Basically, it's a non-electric idle speed solenoid, or "damper." It's rare to see one in good operating condition. Most people removed them to avoid the irritation of having a slow return-to-idle, and installed a regular idle speed screw instead. Those idle speed dampers sell for a lot of money when in operating condition.
Lars
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by forman
I just want find out what this is obviously it’s some kind of adjustment ..my 70 does not have this and it’s advertised as a 70 and the numbers match up … maybe it’s a Cali thing who knows
The carb shown in the photo is not a 1970 carb. It looks like the float bowl is a 1970 float bowl, but the airhorn is a 1971-1974 airhorn - note that it does not have the idle vent system with the "doghouse" on the airhorn, and it has the casting "locking tab" (which is broken...) for installation of the ISS bracket, which the 1970 carbs don't have. The throttle lever is also not a 1970 throttle lever - it is a 1971-74 throttle lever with the extra lever for use with the electric ISS (which means the entire throttle plate is not a 1970 component), so the carb is a "mix-n-match" carb that has been "created" from multiple different carbs and years. Don't even consider buying it, because the 1970 float bowl is not compatible with the later year 4MV throttle plates - the fuel and air transfer holes don't line up. The manual, non-electric "dashpots" were replaced with the electric Idle Speed Solenoids (ISS) starting in '71, so that dashpot may be "correct" for the float bowl on the carb shown, but the rest of the carb is a pieced-together pile of junk...
From: At my Bar drinking and wrenching in Lafayette Colorado
For info:
This is a "correct" 7040207 (1970 Vette 350 Federal emissions manual transmission) Q-Jet with the "dashpot." It looks like this:
1970 float bowls can also look like this, which is what the float bowl is in the OPs photo above (7040204 bowl). Note that there is no provision for attachment of an electric ISS bracket, so the "dashpot" system was used:
Look at the 1970 airhorn and compare it to the photo posted of the "1970" carb in the OP's first post in the area around the forward, driver's side mounting bolt hole: There is no provision for installation of the ISS bracket on the "real" 1970 airhorn. Also, look at the correct 1970 throttle lever in this photo and compare to the lever in the OP's photo:
Be very critical when buying used carbs - they are often not what the sellers are representing them as... fake hack-jobs are common, and you can't successfully rebuild a carb that has been pieced together with mismatched components.
From: At my Bar drinking and wrenching in Lafayette Colorado
Somebody found themselves a 1970 454 float bowl and then pieced together the rest of the carb using 1971-1973 small block carb parts... total scam. Look at the ad just right above the one you found:
This is a real "205" carb. Note the throttle lever on the real carb: The lower part of the lever is cut off to clear the big block manifold. The lever on the carb you found is a small block post-70 lever that is not cut, which means the throttle plate is not the right plate for the '70 BB (which means the idle air bleeds in the plate are all wrong for a 454). Note also the correct airhorn on the "junky" carb I linked above with the "doghouse" bowl vent - all missing from the carb in your ad. 1970 was the last year for the "doghouse" vent, so the airhorn without the vent is a post-'70 airhorn.
I got this in a trade deal about 10 years ago from the looks of it it appears to be painted or metal painted I have never tried to do anything to it but appears to be rebuilt 7040205
uilt
From: At my Bar drinking and wrenching in Lafayette Colorado
Yup, that's a hacked, painted carb. I sure wouldn't want to touch that one. It also looks like the throttle plate has a pipe plug in the vacuum hole in the back edge of the throttle plate... the 1969 and 1970 Chevy Q-Jets did not have a vacuum hole in the back of the plate, so the throttle plate has either been altered, or it's not a correct throttle plate for the carb.
This is a correct 1970 - note no vacuum fitting provision in the back edge of the throttle plate:
Carb part ID
