Chevy 350 quadrajet on Buick 455

[josehf34]

Hello Guys!

I came here trying to look for some specialized help with a Quadrajet. My car is a 70 Buick 455, manual transmission and 2.93s in the rear and I'm trying to make it run with the quadrajet that it had when I bought it (The original unit is missing).

The carb is a '78 Chevy Quadrajet #17058213 which according to the number belongs to a manual 350 Chevrolet. Since my engine is all stock and I'm not planning to do something really wild to it I think the 750 CFMs from this carb could be enough to make the engine breath, or at least that's what I want to try before looking for a 800CFM QJet.

Somebody in the past tried to remove the down channel restrictors and idle tubes due to it was idling too lean and it ended destroying both elements. According to what I know about Qjets this parts needs to be drilled in order to make a Qjet from a smaller engine properly idle on a bigger engine. So I was looking for the idle tubes and down channel restrictors and found them on quadrajetpower.com, but I'm not sure which size should I buy.

I live at 5600ft of altitude so I'm sure that needs to be taking in mind when buying or drilling the tubes.

Tubes:  https://quadrajetpower.com/idle-pickup-tubes-new-pair/
Channel restrictors: https://quadrajetpower.com/down-channel-restrictions-pair-new/

What else modification has to be performed on this carb to properly perform on my 455?

[Cliff Ruggles]

That carb can be made to work on the 1970 Buick 455 but is a very poor fit.

Throttle linkage is completely different, side fuel inlet instead of a front inlet, choke linkage not the same, etc.

The carb is "hacked" a bit and from what I can see the power piston hanger arms are bent some as well.

To effectively use the Chevy truck carb on the big 455 Buick engine it will need some additional parts besides idle tubes and DCR's. 

I would call the shop and order one of our rebuild kits.  We will switch out the N/S assembly to the high flow used in the Buick carb, and shorter accl pump, and include jets, metering rods, PP spring and the correct idle tubes and DCR's for what you are doing.

You will need to remove the DCR's and idle tubes to install new ones and not "hack" up the holes they are pressed into during that process.

If it were mine I would source out a 1970-74 Buick carb right to start with and build it instead, rather than try to use something that just doesn't fit well anyplace.  Buick Q-jets from that period are actually very common and readily available.  I have several dozen of them here in the core pile and may even have a 7040240 from a 1970 Buick 455........Cliff

[lightning boy]

make sure your carb #is not 17058218 the last 8 is lightly stamped on one side and sometimes looks like a 3 ! That should be for a 78 chevy truck. Not a 17058213