Should I stick with stock carb or aftermarket?

[C10Silverado79]

I'm looking for some opinions from those who know much more than I do. I'm planning on using my truck for a mix of occasional commuting, hauling, and towing. I'm looking for reliability, and as decent of mileage as I can get with a 350 but still have some power when it's needed.

Do I go with a rebuilt stock carb or is there some other brand/model that might be better to install? I'm not looking to do a major rebuild. I'd just like to get the motor running as well as possible.

Thanks,
Steve

[msgross]

As far as decent mileage with power when you need it I don't think there is anything wrong with a rebuilt quadrajet style carb. Check NAPA... Why not just have yours rebuilt?

[raws67]

I agree I like a good quadrajet. As long as you dont always lay in to those secondaries you will get decent mileage from one.

[old Rusty C10]

anything aftermarket will not give you decent mileage... then again these trucks do not give you decent gas mileage..stick with the quadrajet

[suville]

Definately Q-jet!And I would highly recommend SMI.
www.smicarburetor.com

[C10Silverado79]

yea, I know I'll never get great milage with the truck but I want to get the best that I can. So far it's pretty unanimous to keep the Q-jet. That is ok by me, I just did not want to spend some $$$ on it only to find that for a couple $$ more I could have had something more suitable.

Are the Q-jet's difficult to rebuild? Is it worth the effort or am I better off just buying a rebuilt one?

[camshaftgsxr]

Am i the only one here who doesn't like Q-jets?

but for gas milage i'd go stock Q with a fresh rebuild

[60ratrod]

as with the some on this board and most in this thread, keep the q-jet. but if i'm going to be replacing the carb for any reason what so ever then i go with the simple edelbrocks. but a good and properly rebuilt and tuned q-jet can out perform any aftermarket on the road

[MTCK]

One more vote for the q-jet. More important that carb x or y is to get it running perfectly. I was having erratic performance with mine and dug into the distributor to find the mechanical advance was rusty and one spring was broken causing it to be stuck with no advance.... There are some good books to walk you through a rebuild. I would check out amazon or your local book store. If this is your daily driver I like my quadrajet for it's cold weather performance. The high idle is nice. Make sure you have the proper jets for your application and you will be happy with the mileage and throttle response with the small primaries.

[msgross]

I assume that you already have HEI as well? If not then you can't go wrong with that upgrade...

rebuild kits for Q-jets are cheap, get a new float and a book and try it out... There are some tips online about sealing it up better than stock too...

[C10Silverado79]

One more question for you guys. Would it be worth the trouble/effort to look for a newer TBI setup?

[60ratrod]

factory tbi setups are getting easier to install on older vehicles today. all you really need is either the tbi intake or and adapter. then its just swapping in the harness and ecu

[qu1cks1lver56]

Holley 600 vacuum secondary is where its at. I have one and the fuel economy isn't too bad, and the power is definitely there. And I know how to work on a holley, get me around a quadrajet and I'm lost.

[spinem]

stock quadrabog will give u better mpg, holley or ebrock will give u more power, less mpg. (were talking 2gpm and like 10hp) no huge numbers, but still, numbers.

DONT GO TO NAPA!!!!!! ive seen about 1 in 4 good carbs while working there, have yours rebuilt. 200 bucks usually.

[Kaysenmc]

Originally Posted by spinem

(were talking 2gpm and like 10hp) no huge numbers, but still, numbers

2 gallons per mile is alot!!

I have rebuilt alot of quadrajets and they are really fairly simple once you get into them. Pick up a good rebuild kit and new float (this will run around 30 bucks) and tear into it. Just take your time and you can do it.

[raws67]

One of the biggest problems with the quadrajet rebuild is if it has worn throttle shafts so pay attention to that if you decide to rebuild your factory q-jet. I like to pull them apart and soak them overnight in hot soapy water and then take a brush and clean away. Then if the wife doesnt find out I throw the big parts in the dishwasher and let em get nice and clean. For a final clean I spray all the ports with carb clean then blow them out with compressed air. They are a very simple carb once you get the hang of them. I have to believe there was a reason GM put em on every model for many many years. There just a damn good carb and a properly rebuilt one works great.

[C10Silverado79]

Sounds like a carb rebuild is problably the most logical choice. I'll have to wait and see if I want to rebuild myself or buy a rebuild carb. Regardless, nothing is happening till this flippin weather warms up.

[spinem]

Originally Posted by spinem

View Post
(were talking 2gpm and like 10hp) no huge numbers, but still, numbers

Originally Posted by Kaysenmc

2 gallons per mile is alot!!

I have rebuilt alot of quadrajets and they are really fairly simple once you get into them. Pick up a good rebuild kit and new float (this will run around 30 bucks) and tear into it. Just take your time and you can do it.

...

[Mike C]

Another vote for the Q-jet.

I have run 750 Holleys, 600 Holleys, 650 Holleys, stock Q-jets, and currently a JET Stage II 750 cfm Q-jet on my Jimmy. Hands down the JET is the winner in driveability and economy. I noticed no power difference either. But the motor is not a maximum output effort, but a max drivability package. VERY happy with the JET.

I ran the same JET carb on my 70 402 truck and was equally pleased there. Currently I picked up a Summit electric choke Q-jet for my 86 K30 454 but have not installed it to be able to comment. But one thing I know, it will be a DRAMATIC improvement over the 750 Holley the previous owner installed that might only get 25% throttle because they kludged the linkage. Which is just one more reason to stick with a Q-jet.

[68Timber]

Another vote for the Quadrajet, but don't buy a reman. There's a lot of junk coming over the counters that really needs to go straight to the junkyard. Get yours rebuilt by someone who knows what they're doing or do it yourself if you like.

[longbedrick]

convert to a 2 barrel carb and intake. then you don't have the option of opening up those secondaries

[C-10 simplex]

Also, i'm pretty sure(until convinced otherwise by verifyable proof) that keeping the stock air cleaner assembly is going to get you max mpg.

The first thing EVERYONE wants to do is replace the stock aircleaner with some open element thing.

a)i only think this is advantageous, in terms of power, at WOT. And even then on a stock engine, it's not that much more power.

b) The stock aircleaner, if it has a hose attached to the front of the vehicle for cold air, will also provide cold air at WOT because at WOT vacuum goes away---which opens the door on the snorkle, thus only colder air goes to the carb. In this case, the benefits of the open element aircleaner are nullified especially on a stock engine?

[Slofarmtruck]

Originally Posted by C-10 simplex

Also, i'm pretty sure(until convinced otherwise by verifyable proof) that keeping the stock air cleaner assembly is going to get you max mpg.

The first thing EVERYONE wants to do is replace the stock aircleaner with some open element thing.

a)i only think this is advantageous, in terms of power, at WOT. And even then on a stock engine, it's not that much more power.

b) The stock aircleaner, if it has a hose attached to the front of the vehicle for cold air, will also provide cold air at WOT because at WOT vacuum goes away---which opens the door on the snorkle, thus only colder air goes to the carb. In this case, the benefits of the open element aircleaner are nullified especially on a stock engine?

I agree but disagree. The snorkle is still the limiting factor in your equation as it only allows so much air into the engine. Now some may argue that increase in air requires an increase in fuel which will negate all the improvements I am trying to make. Well theoretically the more air being drawn into the motor should require the throttle to be opened less therefore using less fuel. Remember the engine is just an air pump. Easier it is to get the air in and out the more efficient the engine runs. I say toss the stock stuff and get yourself a good open element. Now there is the other argument of the open element sucking in only hot air from on top of the engine. This may be true while sitting at a stop light, but while the vehicle is moving it will be sucking in air that is colder than the engine and will have the same if not better effects than the stock snorkel. I know my theory's are rough but I have seen dyno proof to make me a beleiver and not always at WOT.

[GMC Guy]

Originally Posted by Slofarmtruck

I agree but disagree. The snorkle is still the limiting factor in your equation as it only allows so much air into the engine. Now some may argue that increase in air requires an increase in fuel which will negate all the improvements I am trying to make. Well theoretically the more air being drawn into the motor should require the throttle to be opened less therefore using less fuel. Remember the engine is just an air pump. Easier it is to get the air in and out the more efficient the engine runs. I say toss the stock stuff and get yourself a good open element. Now there is the other argument of the open element sucking in only hot air from on top of the engine. This may be true while sitting at a stop light, but while the vehicle is moving it will be sucking in air that is colder than the engine and will have the same if not better effects than the stock snorkel. I know my theory's are rough but I have seen dyno proof to make me a beleiver and not always at WOT.

x2
when that fan is pushing mass amounts of cold air into the engine, the open element is sucking it right down the carb. but i also see the "ram air" theory. i thought about running that dual snorkel air cleaner with a open lid like a K&N. that way, theoretically, you would get the best of both worlds.

oh and another vote for the Q-Jet.

[MTCK]

Another thought on the snorkle (and the reason I run one in the winter) is that you can feed your carb a more consistent density (temp) of air. This is very important when you are tuning for performance or efficiency and in PA I bet you see 40-50 degrees of temp swing in a month during the winter? There is a temp switch inside your air box that controls the flapper as well as vacuum, so the engine will pull cool air once it is warmed up regardless of throttle position. You should be able to do one tune of your idle air mixture and then leave it if your snorkle is working properly.