Need some help and parts for my 17058213 Build for my Big10 Truck from 1978

[Kent]

I have a nice core here and I would like to build a perfect carb for long trips with my BIG10 1978 with camper top. So gas mileage and also torque are most important if I haul a trailer with a car etc.


I bought Cliff´s Book but I didnt had time to start to read it and I will be in the US in 3 weeks so I would like to order some parts to my address there.

What would be the perfect setup for such a carb. I miss the divorced choke also. Otherwise my engine was overhauled and recieved a RV Cam and Headers. It has good torque.

So I would need to buy a kit that will allow me to work on my carb when I´m back from the USA and I hope I dont need more parts then.

What kind of tweaks are ok and necessary? Here is a list of some stuff a guy on Ebay is doing. Is that all good?


...throttle shaft bushings replaced with 5/8” wide Oillite bronze equivalent..permanently eliminate vacuum leaks past shaft ...stainless steel screws and Locktite on reassembly...throttle blades indexed to factory positioning in both bores...very smooth throttle movement.
...all primary and secondary fuel well plugs sealed with 2k epoxy…oven cured.
...base plate sealed APT plug and screw have been carefully removed and replaced with a external screw. This allows exterior adjustment to the part throttle air/fuel ratio. Nice tuner mod to take advantage of the “B” primary rods taper up or down sizes in their jets…very nice mod.
...idle mixture holes enlarged to allow full range of idle air/fuel mixtures., just like the earlier versions.
...slightly modified idle tubes and idle channel restrictions.
...accelerator shooter holes slightly enlarged and tested to spray two fast solid streams...accelerator pump duration shot linkage added to allow fast changes.
…main and idle bleeds reworked.
...secondary air flaps "notched" to allow instant spray under full throttle...secondary Pull over enrichment holes enlarged for a richer initial shot of fuel...secondary fuel well restrictor holes enlarged for faster refill after a full throttle RIP...secondary emulsion tubes and channels slightly enlarged to eliminate the “dog-leg” restriction...primary to secondary linkage adjusted for fastest response…CFM limiter tab carefully removed and modified for a adjustable set screw...set it mild to wild just by turning a screw for maximum 750 plus CFM flow…these mods will eliminate any lag/bog under full throttle.
...70 primary jet …45 B primary rod.
...secondary rod CP (.057”)..hanger I.

[novadude]

My $0.02.

...all primary and secondary fuel well plugs sealed with 2k epoxy…oven cured.

Not necessary in most cases.  If the plugs are leaking, epoxy is not the best way to fix.

...accelerator shooter holes slightly enlarged and tested to spray two fast solid streams...accelerator pump duration shot linkage added to allow fast changes.

Don't touch the accelerator pump nozzles if this is a mild engine and economy is the goal

secondary emulsion tubes and channels slightly enlarged to eliminate the “dog-leg” restriction...

Not sure what he is talking about here with regards to enlarging channels.  If he is talking about the angled channels that lead to the main secondary wells, You'd need to pull the bottom plugs to enlarge these.  Not necessary in your application (maybe not necessary in any application).

CFM limiter tab carefully removed and modified for a adjustable set screw...

Also not really necessary.  Just file the tab on the air door linkage a bit if the door opening is too limited.  The air door opening dimensions in Cliff's book are a good guideline for this.

Just my opinion...

[Kent]

Thank you for the answer, so what would be necessary the APT and something else? Which kit would work to make the carb work again and to calibrate it.

[novadude]

I would probably contact Cliff... he can point you in the right direction, and the parts / rebuild kits are nicer than what many of the carb shops are selling.  For what you are doing, stock calibrations will probably be pretty close to correct.

[lightning boy]

Awesome truck!
Yeah, just call Cliff he will give you the set up, and has the best parts anywhere.

[Kent]

Is Cliff not reading here?

[Kent]

Another question I have read at Hemmings or somewhere there are modified Accelerator Check Valves you can buy from mikes carbs parts WA and special squirter from quadrajet parts NJ what is going on with these special parts?

[novadude]

Another question I have read at Hemmings or somewhere there are modified Accelerator Check Valves you can buy from mikes carbs parts WA and special squirter from quadrajet parts NJ what is going on with these special parts?

No idea what they might be talking about?  Pump check valve is just a steel ball in these carbs, and squirters are drilled into the casting and not replaceable in these carburetors.  IMO and experience, the Q-jet accelerator pump almost never needs calibration changes on a mild cam, dual plane application.  Whatever came in the carb you are working with is usually fine.

[Kent]

This is the description from a guy who is rebuilding these carbs, what are you thinking?

Rochester Quadrajet 17058213 1978 CHEVROLET/GMC 350. ..Condition is Remanufactured…no core charge.
…if you have modified your engine , you want this Quadrajet.
...modified idle, part throttle and full throttle for performance/tuner.
...750cfm single main air bleed version...very nice core...fully disassembled...soda media blast cabinet…every passage opened with fine wire, brushes and shop air…nothing left untouched.
...throttle shaft bushings replaced with 5/8” wide Oillite bronze equivalent..permanently eliminate vacuum leaks past shaft ...stainless steel screws and Locktite on reassembly...throttle blades indexed to factory positioning in both bores...very smooth throttle movement.
...all primary and secondary fuel well plugs sealed with 2k epoxy…oven cured.
...base plate sealed APT plug and screw have been carefully removed and replaced with a external screw. This allows exterior adjustment to the part throttle air/fuel ratio. Nice tuner mod to take advantage of the “B” primary rods taper up or down sizes in their jets…very nice mod.
...idle mixture holes enlarged to allow full range of idle air/fuel mixtures., just like the earlier versions.
...slightly modified idle tubes and idle channel restrictions.
...accelerator shooter holes slightly enlarged and tested to spray two fast solid streams...accelerator pump duration shot linkage added to allow fast changes.
…main and idle bleeds reworked.
...secondary air flaps "notched" to allow instant spray under full throttle...secondary Pull over enrichment holes enlarged for a richer initial shot of fuel...secondary fuel well restrictor holes enlarged for faster refill after a full throttle RIP...secondary emulsion tubes and channels slightly enlarged to eliminate the “dog-leg” restriction...primary to secondary linkage adjusted for fastest response…CFM limiter tab carefully removed and modified for a adjustable set screw...set it mild to wild just by turning a screw for maximum 750 plus CFM flow…these mods will eliminate any lag/bog under full throttle.
...70 primary jet …45 B primary rod.
...secondary rod CP (.057”)..hanger I.
...rebuilt with high quality kit including new (Fl-8 max capacity float, .130” needle/seat, ethanol resistant blue seal accelerator pump, thick gaskets, tested/polished/painted secondary/choke dashpot ...short style fuel filter with fitting/o-ring/spring..air cleaner lid gasket and baseplate gasket included.
...common divorced choke set up used on many 1973 to 78 Chevy/GMC car and truck.