carb setup input please.

[292farmer]

so im trying to decide which carb set up would be best for my truck, its a 292 I6 backed by a sm465 and a 5.13 rear end. im looking at a dual 2bbl carb set up at a total of 450$ estimate. and a 1x4bbl set up at 420-480$ estimate.
i know the 2x2bbl would look the coolest, however which set up would perform best in a 4500lb truck, that's a DD, play and a work truck? would the twin carbs give me trouble towing?
also im looking at two carbs for the 4bbl a 500cfm edelbrock @ 255$ and a q jet @ 219$.
can a q jet be tuned for a I6 if i remember i read in a book q-jets can be from 350-750cfm and some were on a pontiac I6 (sprint?). can any q-jet be tuned for an inline 6 cfm? or do i have to find a specific casting of q-jet for the smaller cfm of 350-500? would a stock sbc q jet work with a little tuning?
thanks everyone and yes i know i need the inline 6 power manual...sigh i forget everytime i drive past the book store...

[Wrenchbender Ret]

I'm a strong proponant of Q-jet's but on an engine that's pulling hard a lot they are not practical. A small Holley or Carter 4 brl. would work best.

[292farmer]

why are they not practical? to lean? that may actually work for a inline 6, as they draw less air and fuel then a v8. idk hence why im asking.
any thoughts on a dual carb setup in a working truck? thanks in advance

[Wrenchbender Ret]

The primaries are too small for a truck that is working hard. You are into the secondaries too much. That's why GM didn't put them on the 1 1/2 ton up trucks. They used large 2 barrel or Holley 4 brls.

[292farmer]

hmmm that does make sense. will it at least work well until i can afford a holley or such? as people seem to love to toss the q-jets around here. plus im sure the 5.13 gearing will take some of the load off the carb. thank you for your help so far wrenchbender.

[Wrenchbender Ret]

I don't know what manifold you have in mind but the Q-jet's & square bores have different bolt patterns & you will have to modify throttle linkage & fuel inlet tubes to change over. It would not be worth it unless you plan on useing that style carb. I agree Q-jet's are cheap. You can buy them for $5 to $10 at the swap meets. $50 or less in parts & you have a great performing carb.

[292farmer]

i plan on an offy intake, with an alum adapter hoping 1/2" thick(having napa make me one 15-20$ ). fuel lines are rusty so im replacing them all so modifying to fit is not a problem, and linkage i figure i have to buy or make no matter the carb i get.
i figure 50$ q-jet 230$ intake(new) 20$ adapter 30$ roll fuel line and fittings 50$ linkage, that makes 380$ where just the 500cfm edelbrock (255$) and intake(230$) is 485$ and i'd still need fuel lines and linkage...
by working hard u mean while towing and hauling right, i tow 1-2 times a week roughly 1500-2200lbs, and haul 800-1500lbs 2-3 times week usually these are same days.
do u still feel this is too much for a q-jet? what percentage would u feel the mileage would drop? 30-50%? im living with 13mpg now, figure 15-16mpg when 4.11's replace the current 5.13s, so the occasional drop in mpg would be fine plus the 100$ or more i save with the q-jet would give me extra gas money for those days.
i'm not saying i don't believe you with the q-jets not being good work carbs, im just trying to use your knowledge to see if the monetary up front savings of using the q-jet would be worth it. my experience with holleys/edelbrocks is not the best. thank you so much for your help so far.

[Wrenchbender Ret]

It's hard to tell without trying. Be sure you have a good exhaust system. The stock exhaust on a 292 gets extremly hot when its working hard. It warps manifolds & burns out gaskets.

[292farmer]

i should of mentioned i have clifford shorty headers on it now with dual 2.25in pipes straight back to two 28" thrush glasspacks that exit in front of rear axle.
so i guess i'll give it a shot hopefully i get all the money together soon, at least if the carb don't work out its only 50$ and not 200+$!
btw is it the throttle shafts that create a vacumn leak on q-jets as they wear? is their a way to tell if they are worn to that point, from looking at it at the parts yard? i know its fixable just figured i'd try to act smart when i go lol.
thanks for all your help.

[timber rattlesnake]

Originally Posted by 292farmer

i plan on an offy intake, with an alum adapter hoping 1/2" thick(having napa make me one 15-20$ ). fuel lines are rusty so im replacing them all so modifying to fit is not a problem, and linkage i figure i have to buy or make no matter the carb i get.
i figure 50$ q-jet 230$ intake(new) 20$ adapter 30$ roll fuel line and fittings 50$ linkage, that makes 380$ where just the 500cfm edelbrock (255$) and intake(230$) is 485$ and i'd still need fuel lines and linkage...
by working hard u mean while towing and hauling right, i tow 1-2 times a week roughly 1500-2200lbs, and haul 800-1500lbs 2-3 times week usually these are same days.
do u still feel this is too much for a q-jet? what percentage would u feel the mileage would drop? 30-50%? im living with 13mpg now, figure 15-16mpg when 4.11's replace the current 5.13s, so the occasional drop in mpg would be fine plus the 100$ or more i save with the q-jet would give me extra gas money for those days.
i'm not saying i don't believe you with the q-jets not being good work carbs, im just trying to use your knowledge to see if the monetary up front savings of using the q-jet would be worth it. my experience with holleys/edelbrocks is not the best. thank you so much for your help so far.

stick with the qudra junk carb they have half as many problems as holly with the accel pump and the power valves also an I6 engine on its best day perfectly dynoed with the largest cam u can fit might pull 500cfm and acually use it all so go with the one four barrel quadra junk carb and be happy they are good carbs and dirt cheap i have ran them for years with alot less headaches than with hollys or double carb setups

[geezer#99]

I put a 350 holley 2 barrel on my Offy. Float bowl towards the valve cover. I lowered the float a quarter inch, bolted it on, set the idle screws at 2 turns, fired it up and haven't touched it in 6 months. Quadrajets are great carbs but too much for your 292. JMHO
If you want the look of a quad but with bigger primaries look for a dueljet. They're a 4 barrel quad with a blanked off secondary but with bigger primaries.
I'll post some pics of mine when I get home. Stuck in Hawaii till saturday. POOR Me!!!!

[292farmer]

yeah definitely liking the q-jet idea. my dad was saying too of the hassle of keeping dual carbs tuned/synced?. the dualjet wasn't that on the 301 pontiac v8? or at least thats the one motor i remember them being on. guess i'll see which ones i get my hands on first, thanks guys.
btw went to borders but didn't see any book on quadrajets isn't their a good book out their about working with them? or is my memory fuzzy?

[geezer#99]

Look on Amazon.com for quadrajet books. Dualjet was on some 350's too.
Here's pics of my Holley 350 on my 65 230.

[292farmer]

beautiful! thats an offy intake right? i may look at amazon i just hate buying online, as i got no cards have to go load a walmart one when i do online orders lol. but it keeps me debt free.
i may consider a holley if i can get the money or a great deal on one. its just i got to watch my spending i got a little one on the way and id rather spend more on him then my truck. thanks for the pics and advice!

[geezer#99]

Yup. It's an Offy. Here's some quad links for you.
http://www.florida4x4.com/tech/quadrajet/
http://www.vetteprojects.com/kstyer/quadrajet.htm