which q-jet to build

Was hoping to get a few opinions. I have two carbs for a mildly built 455. It has a sort of large cam (dont know exact specs but sort of lumpy idle). The carb it came with is a 795 cfm edelbrock q-jet (1904?) for a smog era chevy 454. It runs pretty bad... Im thinking it is mostly the main jet spring needs to be softer since my vacuum at idle is a little low but there is off idle slumbling and full throttle hesitation too. I also have a carb from a 69 430 but it has the spring in the manifold choke set up(i have an aluminum performer) and the old style float. Which carb would be the best for a streetable build? I was planning on getting Cliffs book and kit for whichever one.
Thanks

 

first : cliff , ken or mark will give ya a more definitive specific answer but i would be tempted to use the edelbrock ( ken has a 1904 for sale now at his vendor site below ) . the 430 carb may look a little more OEM but from what i've read the edelbrock may have some "run" advantages .
the cam specs would help alot . all three are gonna ask ya the same basic questions - cam , compression , intake , gear , car weight , trans , drive style etc .
cliff's book covers both the OEM q-jets and the edelbrock versions .

 

Your best bet is to order a rebuilt carb for your engine specs... Ken from Everyday Performance is great to deal with and will calibrate the engine custom to match your car. You can either send one of your carbs to him or have him send you one of his cores...

I would use the Edelbrock carb you have, they are very nice carbs! Send that to him, then bolt it on and go...

 

Get the correct Q jet core. They are cheap.

 

Either carb is a good stating point

The Edelbrock 1904 is calibrated for chevy engines. It will just be plain wrong for a BBB455, especially with a mild cam.
It has its advantages though.....electric choke.....APT accessible thru the air horn....could be built up like a 1910 Performer RPM for BigBlocks

On the other hand, the Buick carb will look right, and in stock form is better suited to your engine than the Eddie in stock form.

In EITHER case youll need to have it recalibrated for your combo.

For me it would come down to a choice between Electric Choke on not.

 

I agree with Ken, on the electric choke or no choke decision. I don't run a choke on mine.
Once you decide that, I would get a 71-74 Buick 455 quadrajet for no choke, and a 76 Buick 455 Quadrajet if you want electric choke. All of those were rated at 800 cfm and will be close to what you need in set up. But any will require some modifications to the idle circuit to work best with an aftermarket cam.

The 430 carb is 750 cfm. A fine carb, but I recommend the later versions.

If you get Cliffs book, and get parts from him for your build, he will also help with your proper jetting and rods you will need.

 

Thanks for the advice guys. So sounds like I should be on the look out for a 76 455 carb since I want a choke or do some heavy mods to the edelbrock. I havent the slightest clue what the cam is unfortunatly. It came with the motor and is pretty lumpy....Ill probably swap it with something smaller at some point.As far as the engine specs... Performer intake, big 3.5" collector long tube headers, stock 73 heads, 9.5:1 hypereutectics (i could read the part number with my borescope). Msd box and billet distributor. Stock 2.73 gears (8.2... yeah I know... thats my next step...) with a th400, slight stall, maybe 2200?.. stock 2 door skylark otherwise. The car is mostly just to cruise on the weekends and do burnouts. I might take it to the track at some point. Ill get cliffs book and do some reading. I would like the experience of building it myself to learn quadrajet tuning.

 

Will do once I get my tools out of storage next week. Thanks Larry. What rpm do you suggest as a baseline? (It idles pretty rough at 600).

 

I's go with the 1904, far superior in nearly every respect to the original carburetor. It just needs a little help for what you are doing, but will yield a much better end result. The e-choke is a really nice feature, allows for any intake, spacer, etc to be used under the carb, and no heat in the intake is required to make it work. The 1904 is equal in potential the 1910 (850cfm), and takes all the same components. It just has much smaller idle tubes, and not nearly enough bypass air or idle/off idlefuel for a 455 with a pretty big cam in it......Cliff

 

Thanks Cliff. Yeah the electric choke is a must have for me at least. I was planning on getting your high performance kit but need to know which idle tubes you reccomend and which inlet valve size. Ill give you a call to order once I get my vacuum specs and have read through your book. Thanks for the help.

 

Just supply the vacuum at idle information when you place the order, we'll spec out the right idle tubes for what you are doing....tks....Cliff