Carb Help

[77ChevySharkBite]

Hey guys I need some help, I found a great deal on some carbs. I just want to know if this style will fit for my motor it's a Chevy SBC 305.

These are not mine but I'm looking to purchase I just want to make sure they'll work before I go buy them.

http://houston.craigslist.org/pts/3934974470.html

[Redcap]

Depends on if your intake is squarebore or spreadbore.

[77ChevySharkBite]

Well it's a stock intake and I believe the stock is spreadbore, it's just a future upgrade that I'm going to do so I'm not too worried about the intake at this point I'm really just wanting to know if it will work for my motor and not be overkill.

[Redcap]

For a 305 it is WAY too much carb.

[77ChevySharkBite]

Okay so I should go along the lines of like a 600cfm?

[Redcap]

Originally Posted by 77ChevySharkBite

Okay so I should go along the lines of like a 600cfm?

Tops. I'd actually shoot for more like a 500cfm for that little smallblock.

[77ChevySharkBite]

Well I was going to go for a 600cfm because I do have long tube headers and a exhaust and planning to put a cam in it soon.

[geezer#99]

Stock quadrajet carbis rated at 725 cfm. Even on your 305. THe trick is they're set up with different metering rods, step up springs and the secondary air valve is adjusted to limit the air flow.

[77ChevySharkBite]

Originally Posted by geezer#99

Stock quadrajet carbis rated at 725 cfm. Even on your 305. THe trick is they're set up with different metering rods, step up springs and the secondary air valve is adjusted to limit the air flow.

Okay I'm new to the carb world is there an easier way to explain it? Because I sort of get what your saying but I don't at the same time.

[geezer#99]

The quad is used on motors from six bangers right up to 454's. The factory tunes them for each application. THey tune them for how much fuel they put in the motor and when.
Quadrajet is a very versatile carb.

[77ChevySharkBite]

So am I just better off using the q-jet and just rebuild it?

[INSIDIOUS '86]

A 650 will still run fine on a stock 305 or 350 even. Basic point is being able to get good signal.

Nothing wrong with 4011 carbs but other designs are certainly better but I'm solute the $80 price tag helped you really want those

You can slap on an edelbrock or a cheap holley 500-600 of Craigslist. As long as the Holley 4150-4160 have original parts usually a tune and gasket rebuild and they work good

Up north here about $80-$200 can get you a working holley carb from beat condition to decent.

As for a cam I would save the money and use that upgrade for a future 350 although the summit cams are decently priced if you feel the need to. Headers are a great idea and an edelbrock intake can be found cheap in eBay or Craigslist. I've personally found "bad" intakes on purpose with bad threads and such cause usually I can fix them easy and people stay away from them so they are cheap..er haha.
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[geezer#99]

I would. My 84 305 has shorty heddman's on it with 2 1/4 pipes and flowmaster's and works great.
If you don't know much about carbs it's best to leave it stockish unless of course you got money to burn.
If you put a different cam in go conservative. Around 210 duration and .450 lift.

[77ChevySharkBite]

Well thanks for all the advice fellas I really really appreciate it.

I think for now my final decision is going to be just leave the carb and not do anything and maybe spend a little money on more important items.

[INSIDIOUS '86]

Here's a cam I'm running in my 305 http://m.summitracing.com/parts/sum-1102
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In fact the same cam my friend has in his 350 would be perfect. The crane 266h10 http://m.summitracing.com/parts/crn-10004

[superwade57]

Originally Posted by 77ChevySharkBite

Okay I'm new to the carb world is there an easier way to explain it? Because I sort of get what your saying but I don't at the same time.

Between the way a quadrajet is designed and its tiny little primaries..that is the two barrels the carb uses under normal driving until you kick it down.... its rated at 725 or there's a biggrr one too but its basically impossible to over carb witg a q jet that's part of what makes them so great. I'd rebuild a qjet or rather find someone well versed in qjets specifically to rebuild one for you. Imo one of the best carbs available. Until you run a real big cam. I've hearf but not experienced that they may not wark as well then I'd guess due to a lack of vacuum.
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[77ChevySharkBite]

Originally Posted by superwade57

Between the way a quadrajet is designed and its tiny little primaries..that is the two barrels the carb uses under normal driving until you kick it down.... its rated at 725 or there's a biggrr one too but its basically impossible to over carb witg a q jet that's part of what makes them so great. I'd rebuild a qjet or rather find someone well versed in qjets specifically to rebuild one for you. Imo one of the best carbs available. Until you run a real big cam. I've hearf but not experienced that they may not wark as well then I'd guess due to a lack of vacuum.
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Hey thanks superwade!!

Let me ask you something that might be a sign of needed rebuild I noticed it this past weekend after my truck got warm and was idling good, when I went to crank it up when it first turned over it sounded like it wanted to die but it wouldn't and after about 2 secs it would start idling fine what could maybe cause that? Could it be carb related?
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[superwade57]

If I am understanding maybe the choke needs adjusted is it electric choke?
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[geezer#99]

You can run a big cam, you just need to tune a bit more. Years ago (30 or so years) I ran a dual quadrajet intake on a 350. Nothin' like the kick of a pair of big secondaries!

[77ChevySharkBite]

Originally Posted by superwade57

If I am understanding maybe the choke needs adjusted is it electric choke?
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That I'm not sure of, I've worked on it more than I've truly driven it and actually this is first time it's done it, like I stated earlier all I have done to it is long tube headers and flowmaster 10 series mufflers and then I have all new spark plugs other than that not a thing has been done to it.
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[Sodell]

Might be electric, will have a aluminum looking circle on the left side of carb (from fuel line inlet) bigger than a half dollar, with a black cap and a wire sticking out of it. POst up some pics of your carb.

[77ChevySharkBite]

Okay guys I promise I haven't forgot about y'all yesterday I just wasn't able to open the good to snap some pictures but here's my carb, maybe y'all can better help me.





Thank you all for helping me out and responding to me and helping inform me you guys rock!!
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[INSIDIOUS '86]

See that small little box with a rod coming through in the first pic? That's a bi metal choke. As the intake warms it expands and turn the choke off slowly. They are a early style choke and do wear out I'm not sure if the truck was warm or cold at the time if the pic but that choke butterfly should be closed when its cold
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[77ChevySharkBite]

Okay well the truck is cold I can tell you that so I should adjust that then?
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[INSIDIOUS '86]

Yes adjust it and then try starting the truck and letting it warm up. See if it moves then if its in working condition just adjust it some till it starts and runs like you want it to over the next few days.

Another thing to note is that quadrant jets have press in plugs on the under side of the carb that drip fuel from the fuel bowl. Its a common issue that makes them hard to start at times
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