Which Qjet exactly was on a Chevy 1978 BIG 10

[Kent]

Hello does someone here know which Quadrajet was exactly on the BIG 10 in 1978? I know it was a different one than on the normal C10. Here a picture of the intake.

And which gasket is the right one between the carb and intake? I always see the open one but I ask myself why does it need to be the open one just for all the grooves and channels on the carb and intake? A closed 4 hole would make more sense in my opinion as it would create 4 nice holes for a good signal and even distribution.

[Kenth]

The 1978 "Heavy Duty" C10 carb with divorced choke would be #17058213.

The specification sheet calls for an 1/4" thick open flange gasket.

[Kent]

My intake says climate choke I would say, as there is no evidence for a divorced choke on it. So the part number is maybe not the right one.

[Kenth]

I may be wrong, but isn't there a screw hole to hold the choke beneath the hose in your picture?

[tayto]

all the (original) Big 10/Heavy Half i've seen had a divorced choke

[Kent]

ok I need to check this again. But I was sure I have seen something for a climate choke.

[tayto]

Kent, these would all be Canadian trucks. I know emissions stuff was different. We, for the most part, didn't get CCC carbs until the late 80s. At least this was true for trucks, B & G bodies.

[Cliff Ruggles]

As far as I've seen Canadian Q-jets shared the same applications as USA (except CA) thru 1980.  They may have had different part numbers, some of which aren't in any posted literature.  In the US 1981-up automotive Q-jets were CCC carbs, but vehicles for Canada continued to use non-CCC carburetors well into the 1980's. 

I put a LOT of kits together for them, and quite a few Canadian Q-jet part numbers don't show up in any of my literature or in on-line Google searches, so I usually have to have them send pictures of the carb to complete the order.

In the US, as far as truck applications unless the vehicle was CA emissions they used divorced choke carburetors thru 1978.  Automotive applications were divorced choke thru 1974, then they went to hot-air chokes started using electric chokes in the 1980's.  There were exceptions to this, as Vans and possibly some light duty trucks will have hot-air choke carbs prior to 1979. 

Canadian applications followed suite far as I know thru 1980, or at least I haven't seen any exceptions to date......

[wazzabie]

The 1978 "Heavy Duty" C10 carb with divorced choke would be #17058213.

The specification sheet calls for an 1/4" thick open flange gasket.

I have a 78 K5 Blazer w/ auto tranny that has the 17058213 carb.  Heavy duty federal emissions.  Divorce choke setup.  The factory service manual also calls for this carb in manual tranny non federal.

[Kent]

I found time and checked it and it's a threaded hole so it should be for a divorced choke. Ok then my research was not correct. So it should be the 17058213 ok now the glory question who can sell me a nice numbers matching carb for my BIG 10 which will work perfect.

and is the baseplate on the picture correct for this carb? I have seen different ones for the same number and I think some people changed them due to problems with linkage etc.

[Cliff Ruggles]

I have several 17057213 and 1708213 cores.  I'm retired from rebuilding and restoring carburetors but will gladly supply a nice core and rebuild kit is you can do the work......

[Kent]

Yes if you have a good core that is in a nice condition so I don't need to replate it that would be nice. I think I will be able to overhaul it. is there maybe a good how to I can take a look at? I would like to make the mod with the screw forgot how it was called. Thank you...

p.s Cliff I did send you a message with my contact, thank you...

[Cliff Ruggles]

Best to email me at: 

cliffshp@embarqmail.com

As mentioned I have quite a few 1977 and 1978 Chevy divorced choke truck carbs in the core pile and currently cleaning up and getting rid of most of the cores since I retired from carb rebuilding and restoration......