Thinking about a new carb

[hinkv10]

My truck came with an Edelbrock 1406 electric choke carb. I've played with it a bunch and the truck runs excellent. The problem is I'm getting 8 mpg on a 305 in a short wheel base reg cab pickup with stock tires. She sounds mean with the flowmasters but doesn't have much power.

I replaced the electric choke with a new one from Edelbrock and tuned the air mixture screws 4 full turns out. It was in the teens yesterday and it started with 3 pumps of the gas and instantly fired with a turn of the key. It runs really well.

I'm thinking of getting a Quadrajet and I've done a bit of research on the web. My question is what kind of tuning am I going to have to do. I'll probably go with smi carb based on the input from here but I've never tuned a carb or taken one apart before. What am I getting myself into?

I would love to do it myself but is it worth paying someone to do? I could save $400 in fuel in less than 1500 miles of driving if I can get the mpg above 12. Any input is appreciated, Thanks

 

[Irishman999]

Yeah man you have a problem if its getting 8mpg, at one point I was getting 17MPG in my K1500 with a Carter AFB. I would not give up on the 1406 right away, order the tuning kit and play around with your primary metering rods, springs and jets. Those little covers on top of the carb with the torx screws are designed so you can change stuff out really quick without the risk of dropping stuff down in the carb. Last time I was tuning on mine I just drove around with the kit and a torx driver changing stuff out until it felt good. After you like your tune put the air cleaner back on and adjust the idle screws.

If you have a smartphone there is an app called fuel log, I used that to know exactly what kind of mileage I was getting.

 

[Irishman999]

Im going back to A quadrajet myself since I am assembling a fresh 5.7 for my truck and want everything to look factory. If you dont feel like spending the money on a pre tuned unit thats ready to drop in and want a challenge get this book.

http://www.barnesandnoble.com/w/how...=pla&ean=9781932494181&isbn=9781932494181&r=1

It will tell you everything you need to know about a Q-jet and you can do it yourself.

 

[Jims86]

Yeah man you have a problem if its getting 8mpg, at one point I was getting 17MPG in my K1500 with a Carter AFB. I would not give up on the 1406 right away, order the tuning kit and play around with your primary metering rods, springs and jets. Those little covers on top of the carb with the torx screws are designed so you can change stuff out really quick without the risk of dropping stuff down in the carb. Last time I was tuning on mine I just drove around with the kit and a torx driver changing stuff out until it felt good. After you like your tune put the air cleaner back on and adjust the idle screws.

If you have a smartphone there is an app called fuel log, I used that to know exactly what kind of mileage I was getting.

X 2....most carbs are jetted a little fat from the factory anyways.
That said, you cant beat the 20 mpg possibilty from a properly set up quadrajet.

 

[Irishman999]

X 2....most carbs are jetted a little fat from the factory anyways.
That said, you cant beat the 20 mpg possibilty from a properly set up quadrajet.

Hell yeah jim, the factory setup that was in my current 1406 I got from the hill billy tractor pull event was way off for a 305. You have to consider alot of guys dont want to mess with a carb so they go straight to Autozone and buy a ready to go unit, edelbrock figures its most likely going on someones small block chevy so it comes with a ballpark setting that wont be to lean.

I would have my original Q-jet on the 85 right now if I didnt have that stupid squarebore intake I got a couple years ago. But in all fairness the 1406 is a close second with the simplicity and close performance.

 

[Jims86]

Hell yeah jim, the factory setup that was in my current 1406 I got from the hill billy tractor pull event was way off for a 305. You have to consider alot of guys dont want to mess with a carb so they go straight to Autozone and buy a ready to go unit, edelbrock figures its most likely going on someones small block chevy so it comes with a ballpark setting that wont be to lean.

I would have my original Q-jet on the 85 right now if I didnt have that stupid squarebore intake I got a couple years ago. But in all fairness the 1406 is a close second with the simplicity and close performance.

I hear ya...thats how those carbs got so popular.
regardles of what carb anyone has, a Gunson colortune spark plug is an absolute neccessity.

 

[Irishman999]

I hear ya...thats how those carbs got so popular.
regardles of what carb anyone has, a Gunson colortune spark plug is an absolute neccessity.

Explain that one to me, sounds interesting dude.

 

[Stroked]

Explain that one to me, sounds interesting dude.

Please elaborate, Jim

 

[Jims86]

Its a special spark plug with a lense around the porcelan that allows you to see the color of the flame in the cylinder while you are tuning....Light blue is ideal.
http://www.gunson.co.uk/items/pdf/Products/G4074-English.pdf

 

[Irishman999]

Its a spacial spark plug with a lense around the porcelan that allows you to see the color of the flame in the cylinder while you are tuning....Light blue is ideal.
http://www.gunson.co.uk/items/pdf/Products/G4074-English.pdf

I have herd of this, its actually sold by LMC truck. I was just wondering if it made a difference whether the engine is under load or not. So if you rev it in neutral in your driveway is it the same as when its in gear pullin hard down the road?

 

[Jims86]

You tune idle and off idle to bunson blue or as close as possible then you can check it for a slight yellow at rapid throttle opening, which is the enrichment.
its a very good way to baseline a carb for dyno or road tuning.

 

[Stroked]

I've seen those before but thought maybe they were a gimmick. I'll have to get one and try it out.


Sent from my iPhone 4s using Tapatalk

 

[hinkv10]

interesting. Its actually sold on Amazon too. $66 bucks

What size are our spark plugs, 14mm?

 

[Jims86]

interesting. Its actually sold on Amazon too. $66 bucks

What size are our spark plugs, 14mm?

yeah, I think the threads are 14mmx1.25....somebody confirm that?

 

[hinkv10]

Yesterday i called Scott over at SMI Carb. I purchased a Stage 1 Quadrajet and it should be here within 3 weeks. I'm going to continue driving the truck around in the meantime and recording fuel economy. I think I'm averaging about 10 mpg now. I'll post up the results in a month or so. Thanks for the advice

I thought about doing it myself but with all the stuff going on the timing just isn't right. I need the truck to be operational and not down for more than a day or two.