When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I recently picked up an intake manifold and a 4-barrel carb (Quadrajet 7043250) along with the cables and brackets from a 1972 Cutlass Supreme and intend to install it on my 1971 Cutlass Supreme that has a factory 2-barrel carb. The carb that I bought is used but I found a rebuild kit off Carb Unlimited and the designations are in the following link:
My question is, can I use this Electric Choke Conversion from Carb Unlimited to convert the carb that I am intending on rebuilding to an electric choke? Is it worth it?
The rebuild kit you linked shows the carburetor with an attached hot air choke. The electric choke conversion you linked is for a divorced choke. Does your Qjet have a divorced choke?
Your carb is actually from a 1973 350 Olds (7043250 is a 1973 carb number). It should have an integral hot air choke. That kit you linked is for a carb with a divorced choke and won't work. More to the point, you don't need a "kit", you simply need to replace the hot air choke coil with an electric one. I typically use Standard Motor Products P/N CV329, available from RockAuto. They also sell the special electrical connector. You can wire it as shown in this thread.
The rebuild kit you linked shows the carburetor with an attached hot air choke. The electric choke conversion you linked is for a divorced choke. Does your Qjet have a divorced choke?
I am not sure to tell the difference to be honest. I can post some pictures later this evening. For now, I do have some pictures of the the number and the plastic plate on the choke.
I can't decode Qjet numbers just by looking at them. My mind is filled with too much useless information... like how to brew beer.
Actually, the third digit is the decade - 4 = 1970s, 2 = 1960s. The fourth digit is the year. 7043xxx = 1973 model year. Olds carbs typically (but not always) are in the 250s for the final three digits.
Your carb is actually from a 1973 350 Olds (7043250 is a 1973 carb number). It should have an integral hot air choke. That kit you linked is for a carb with a divorced choke and won't work. More to the point, you don't need a "kit", you simply need to replace the hot air choke coil with an electric one. I typically use Standard Motor Products P/N CV329, available from RockAuto. They also sell the special electrical connector. You can wire it as shown in this thread.
Actually q-jets from 1965-1969 show 702 as the first three digits, 1965-1969 California and altitude applications show 703 as the first three digits, 1970-1975 show 704 as the first three digits and 1976-1979 carbs show 1705 as the first 4 digits. The fourth digit is the application year. The fifth digit is the original application is federal or California. The 6th digit is the GM division and the last digit shows transmission usage with even numbers being automatic, but is not always true. So the q-jet number 7043250 is 1973, federal application, Oldsmobile, and could be an automatic transmission. The last digit may or may not be. For instance the correct q-jet for my 71 automatic 442 is 7041257 and for my 71 4 speed its 7041256, so check you service manual to be sure of the transmission type.
2 things to remember when doing the conversion, the new choke unit grounds through the carb so remove the paper gasket from the old choke unit, second wire the pigtail to a 12 voltage source with the key in the "ON" position. Otherwise it will have power all the time and drain your battery. Good luck.
Actually q-jets from 1965-1969 show 702 as the first three digits, 1965-1969 California and altitude applications show 703 as the first three digits, 1970-1975 show 704 as the first three digits and 1976-1979 carbs show 1705 as the first 4 digits. The fourth digit is the application year. The fifth digit is the original application is federal or California. The 6th digit is the GM division and the last digit shows transmission usage with even numbers being automatic, but is not always true. So the q-jet number 7043250 is 1973, federal application, Oldsmobile, and could be an automatic transmission. The last digit may or may not be. For instance the correct q-jet for my 71 automatic 442 is 7041257 and for my 71 4 speed its 7041256, so check you service manual to be sure of the transmission type.
Your info may apply to Chevy carbs, but not to Oldsmobile carbs. The actual details vary by year, but here's a sample of 1968-70 Oldsmobile carb numbers. This comes from the Oldsmobile Dealer Service Guild bulletins. Odd and even are unrelated to manual vs. automatic. 703xxxx was never used by Oldsmobile. The third digit was always either a "2" for the 1960s or a "4" for the first half of the 1970s. The fifth digit is NOT Calif vs. Federal. Actually, why would Rochester need to indicate Calif vs Fed in BOTH the third and fifth positions?
Here is yet another example. For the 1967 model year, BBOs used the 7027156 Qjet on RWD cars without A.I.R. (ie, on 49-state cars) and the 7027157 Qjet on Calif cars with A.I.R. That pretty much violates every single one of your "rules", since the Calif carb has a "2" in the third position, the same "1" in the fifth position as the 49-state carbs, and the last digit odd/even has no relationship to the trans.
wire the pigtail to a 12 voltage source with the key in the "ON" position.
Wire it through an oil pressure switch as described in the link I provided in my first post in this thread. That way the choke won't heat up if the key is in the RUN position but the engine isn't running.
Well, apparently every source on the web, including Cliff Ruggles, has repeated that bogus info on Qjet carb numbers. Suffice to say that they are all wrong. Here's my "bible" on the subject:
I stand corrected. I have been reading Cliff's q-jet book and that's where the info came from. From the 70 and 71 carbs I've seen it has held true.
I'm not sure what 1970-71 Oldsmobile carbs you've seen, but just about all of them violate the "rules" on numbering:
7040250 was used on 350s with both AT and MT
7040251 was used on 455s with AT
7040255 was used on W-31s with both AT and MT
7040256 was used on W-30s with MT
7040257 was used on 442s and W-33 with AT
7041250 was used on 350s with both AT and MT
7041251 was used on 455s with both AT and MT
Joe - I am really sorry if I somehow offended you, but that is pretty much what I wrote, "The last digit may or may not be. For instance the correct q-jet for my 71 automatic 442 is 7041257 and for my 71 4 speed its 7041256, so check you service manual to be sure of the transmission type.".
Joe - I am really sorry if I somehow offended you, but that is pretty much what I wrote, "The last digit may or may not be. For instance the correct q-jet for my 71 automatic 442 is 7041257 and for my 71 4 speed its 7041256, so check you service manual to be sure of the transmission type.".
No offense taken. My point was that the most common carbs used by Olds in most years are the '250 and '251, and the last digit has nothing to do with the trans. The third digit has nothing to do with Calif vs 49 state and the fifth digit has nothing to do with that either. That wasn't directed at you, but at the bad info that has been repeated on the web. If folks who should know better (like Ruggles) would actually check this stuff out before posting it, the community as a whole would be better informed.
Just rewired my Cruiser wagon's electric choke per Joe's instructions. Works like a dream. You can see this thread for what I went thru before, when Holley ProShops put a 2-barrel choke coi on my rebuild. https://classicoldsmobile.com/forums...-choke-bs.html .
November 20th, 2018, 07:17 AM
