While I was out of town on a business trip earlier this week, a co-worker left a message on my voicemail: "I left you a gift on your chair." When I get back to the office today, I see a grocery sack with a plastic-wrapped q-jet in it.

He said he got it off a 70 Chevelle SS 396. The number is 7040204, which http://www.thecarburetorshop.com/Kchevrolet4.htm and http://www.carbs.net/Kits/corvette.htm say came on a '70 454 auto tranny.

It's missing the pull-off to AV link, the pull-off hose is disconnected, even. The fuel inlet nut has Teflon tape on the threads. The back two airhorn screw areas are slightly depressed (overtightening), but the rest looks okay - without having disassembled it yet, anyway. I'd guess it was owned by someone who wasn't fully clued in.

It has an L hanger and AX rods (longest power tip I think I've ever seen). A strange fuel bowl vent connected to the accelerator pump arm the likes of which I've never seen.

Should be the high CFM version. But, what do you do with this thing? Too valuable to toss, too 24-years-old to justify using.

(BTW, it was a "gift" as a result of a divorce-driven, selling-the-house garage cleaning.)

Sorry about the non-3rd gen-ness. Some guys ask about older q-jets, that's all.

 

My 74 454 convertible has a 7028202 Q-Jet on it (68 SS396 auto)... same temp-sensitive vent valve (look at it closely, you'll discover it's a bi-metal)

Good carb. I wish there was a way to repair those fuel inlet threads, they corrode from electrolysis, it's inevitable no matter how careful the mechanic is..... I have a bunch of great carbs suffering that form of carb Alzheimer's.

If you don't want/need it, I can think of at least one good home for it.

 

I'll have to pull the sheet metal cover & look at the vent. I'll try to post a pic later as well.

After posting and while re-wrapping it, I look more closely and see the airhorn gasket isn't even there. And, there is some warpage from overtightening the front mount through-bolts as well.

It will need a lot of TLC in order to be restored to full health. If I needed an over-the-road gas-mileage, slow-it-down-a-little-bit-at-sea-level carb (read: Sportsman class with 13.00 sec. break at Division V ET finals at Brainard this year), then it may be something to consider. Or, I could just bolt that 750 VS back on...

 

Oh, the Teflon tape is on the fuel line to inlet nut. The fuel bowl looks fine there (w/o having taken the nut out yet - but I've seen a plenty of messed up ones).

 

Here's a pic (finally) showing the wire on the accel lever.

 

And one with the cover removed. At idle, the wire lifts up on the top spring, opening the vent. At about 1/4 throttle, the upper spring is sitting full on the vent stopper, closing it.

 

Yup, that's the usual one... came on all Q-jets from 65-68, and on a few 69s.

The thin piece that the rubber stopper is in, is the bi-metal. That whole assembly is designed to relieve fuel vapor pressure in the bowl at idle. Doesn't seem to have much point, since there's also the bowl vent in the air cleaner. But I guess there must have been some kind of reason for it.

Does it have the "hot idle compensator" on the back of the secondary throttle bores, in the rectangular place in the casting back there that all Q-jets have? That was another bi-metal, that opened an extra idle air passage when the carb body got hot.

Like I said, if you don't want or need it, i can find it a good home.

 

...and apparently on a few '70's...

My brother had a '66 327 Impala SS (275 horse), and I took my driver's test in my dad's '69 350 Impala (300 horse). I don't recall seeing it on either one, but I may not have known what I was looking at.

It doesn't have the other compensator on the back end. It appears to be divorced choke, but has the hot air nipple on the back of the airhorn. Not sure what that's all about.

Still haven't figured out what I'll do with it. The temptation is to fix it up and put it on the 396 (I never had the factory q-jet for it). Justifying that is the main issue now.

 

If you don't want to use it or just store it, why not put it on Ebay? If it really is from a '70 454, its probably worth something nice to someone.