Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor
7029207 transition too rich
bob69:
77cruiser, I hooked up a vac pump on the dist vac adv and it holds vac and the points plate moves as expected. All looks ok.
Kenth:
7029207 idle tubes are in the .038"-.039" range, but i have seen units with .035" as well.
7029202 idle tubes are in the .034"-.035" range.
Only way to reduce idle and off-idle fuel is to replace large idle tubes with smaller.
quadrajam:
bob69, Hopefully the smaller idle tube will fix you up but consider this.
Your original post says you have a stall converter of 1800 rpm, your cam rpm range is 1600 to 5200 rpm and your getting less than optimum MPG in the 1100 to 1500 rpm range at cruise speed.
Maybe better MPG is just not in the cards for those conditions. ...???
I bet it does better at 60 mph down the open road. Does your converter lock up?
I aint know, I,m just axing...
bob69:
Kenth, I have four 7029207's. All are SR carbs. Three have .037 idle tubes, one has .038. All have .053 down channel restrictions. Three have .081/.063 upper/lower idles air bleed. One has .079/.062 iab. The larger iab are on 1982 and 1984 carbs. The smaller iab are on a 1976 carb with the .038 tubes.
The 1976 carb is currently on a 400 sbc and it runs great. The 400 gets better gas milage than the 350 when I keep rpms in the 1200-1500 range. The cams are simular, 214/214 110 lsa on the 400 and 214/224 112 lsa on the 350. The 350 should have better gas milage.
I also have an original 7029202 DH E9 carb. Idle tube -.035, dcr - .053, uiab - .068, liab - .065. It was tested on the 350 and the afrs were leaner than the 207s. But is it due to the smaller tubes, smaller iab, or both.
bob69:
Quadrajam, good points. The 200r4 goes into lock up at 30 mph under light throttle. So the stall should not be an issue at the rpms I'm looking at.
The rpms are below the cam's operating range so it's not making best power, but at light load conditions it does not need a lot of power. When needed the 200r4 will down shift nicely. I should still be able to lean out the carb so it gets better gas milage. I hope.....
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version