bullet1

took #s off from qjet on my 68 400 they are 7045183 k4.did a search looks to have come off from 75 or 76 olds 350 would i need to change jetting in this carb?or will this work fine
thanks for info todd

wmachine

7045183 is not an Olds carb. Next to the last digit on an Olds carb is 5.

7028251 442 AT ex W30
7028253 442 MT ex W30
7028254 W30 all

bullet1

will this carb work for the 400?should i look for another carb that would work better?carb seems to run good but not alot of power seems my 71 350 had a little more power.

wmachine

I don't know what it is for, let alone how well it can work.
I would suggest getting a correct carb.

bullet1

any info on anyone that sells rebuilt ones?custom rebuilt carburetors shows one but had to send for price?what would be a good price?
thanks

Bluevista

The number isn't always a "5" for Oldsmobile. At least not for that carb and others in that general era.
The carb is for a 1975 Cutlass or Delta with a 350, auto and air.

http://newagemetal.com/pages/Oldsmob...le0039_jpg.htm

wmachine

My bad. I believe that is true for original equipment carbs, though, unless that was out the window by '75. It could still be a correct replacement carb (but probably not for a '68 400). Judging from what I've seen with replacement carb numbers and original carb numbers, the replacement carb numbers are usually *not* the same as the original carb numbers. With lots of possible explanations.

BLUE72RAGTOP

from what I've read recently, 75 q-jets had several updates over early ones that could actually work out better performance wise. I'd rebuild what you have unless it has too much play in the shafts. If you had to get a kit to bush those, it may not be cost effective vs. a replacement rebuild.

wmachine

That makes sense to me.

Olds64

If I were in your shoes I would just rebuild it. It would be cheaper to rebuild it and have a local shop put new bushings in the throttle plate. I did this with the Quadrajet on my 71 98 and am happy with the results. It cost $15 for the rebuild kit, $20 for a local small engine shop to put new bushings in the throttle plate, and $5 for an assortment of metering rods, jets, and secondary hangars.

bullet1

would i need to change jets,metering rods to the 68 specifications or leave what is in there?carb seems to idle fine no hesition but does not pick up speed real fast it clips past 80 ok maybe im expecting more than what 400 had?
thanks again for all the help.

Olds64

Change jets and metering rods only if you want to. If you are restoring your car to be "original" then you might want to put the correct quadrajet back on it; however, quadrajets are very versatile. You can get good performance with numerous combinations.

Oldsmobomb

I can not speak to the 1975 Q-jet specifically, but the late 60's Q-jets can absolutely be made to stand up and ROAR. Changing the primary and secondary jets and metering rods, as well as adjusting the secondary throttle valve max opening travel, and the secondary air valve spring tension, will tailor the Q-jet to your specific needs, ie. - cubic inches, intake manifold, cam, etc.

An excellent book on power and economy tuning is "Rochester Carburetors" by Doug Roe & Bill Fisher. ISBN 0-912656-10-7. It may or may not be out of print, I've had my copy for 20 (?) years. It covers the Q-jet extensively, as well as the 4GC that is in many earlier Oldsmobiles. It can be your right hand while you rebuild your Q-jet. I am sure there are other good references for the extremely versatile Q-jet.

Good luck on tuning yours and let us know how it turns out.

bullet1

found correct carb but now have question on vacuum lines?where should the transmission and distributor lines go to on this carb?i have a torker intake on this also?also how are you using choke since this intake does not have mechanical pull down for carb?just wire open and cold start?thanks for info.
todd

Olds64

Negative Ghost Rider. Just buy an electric choke conversion plate for it. IT costs about $15 at Summit.

Distributor goes to ported vacuum and the transmission goes to manifold vacuum.

bullet1

looked on summit not sure what kit im looking for any part#s
thanks

MX442

Todd,
I'm in the process of building a QJet to put on my 68 442, also. I also have a performer intake. Keep us posted.

Check out Gessler head porting. Com for q jet parts.

J-(Chicago)

I personally dislike those 1975/76 carbs.
They are mutant bastards.
Some have 4 primary rods if you count the altitude compensator. Add the secondaries and that makes 6 rods total.
They usually come with 67 jets which also suck in my opinion, but I don't know what you're trying to achieve.

J-(Chicago)

Oh yeah, and the 1975 and later carbs cannot interchange primary rods with the older style.
You should be into one style or the other if operating on them. I have some 75/later
parts here if you need a rod change, but only 2 or 3 sets to choose from.

bullet1

i found original carb but now i need to find a way to add a divorce choke conversion.i found some on carburetion.com but i think i will have to make bracket that will bolt onto where the heat tubes are now on torker intake.should work.

Hydro462

Checkout Cliffs Quadrajets... http://www.cliffshighperformance.com/

He can build you one or get his book and buy the parts from him and build it yourself...

I have one and its fantastic!!! It was originally built by Brad Urban then rebuilt by Cliff...

BLUE72RAGTOP

Cliff knows his stuff. I've spoken with him several times and bought his book, a rebuild kit, and a core from him. He always seems willing to help and can recommend upgrades if it's a non-stock application. He has quite a backlog if you want to have him build one for you, though.