Question about Quadrajet (and general running) 454 at high altitude

[dbreid]

All,
I am very excited to be finally heading up to the Dusy-Ershim trail in a few weeks, and I am trying to go through my truck and make sure anything that needs to be maintained is maintained, and anything that needs to be tightened is tight, and anything that needs to be adjusted is adjusted BEFORE I go.

And it occurred to me (probably not a shock) that at altitude (10,000 feet) there will be a lot less air, and therefore, with the jetting in my carb, I'll likely be running rich. Not to mention I will have less power (less air = less power).

Are there things I can adjust when I get there to help it run a little better? The 454 has so much power that even with a loss, I'll probably be fine, I just don't like the idea of running rich for 4 days, and burning all my fuel doing nothing.

Also, in your answers, assume I know very little about carbs. I get the concepts, and have worked on them lightly (fixed stuck floats, cleaned them, etc), but never done many adjustments, or tuning, or re-jetting etc.

Thanks in advance!

-Dan

 

[Hogback Fabrication]

I've run my Q-jet between 3,000 and 11,500 ft and I've never changed jets for a single trip like your suggesting. Honestly, I never noticed the truck running super rich or lean. Of course you notice some difference but most of that is due to lower air pressure at high altitudes (which you already mentioned).

IMO, don't worry about.

 

[dbreid]

Hmmm... I love it when advice doesn't cost me anything. How about oil? I have never spent a week (4-5 days) at 10K feet. Should I change anything else?

 

[apache]

The entire trip isnt at 10K feet,just parts. I frequent the area pretty often over kaiser pass and hit Courtwright alot and really never had any problems,make sure your air filter is fresh and you might need to adjust the idle mix screws worst case but probably not at that even. If your runnin the Dusy id be more worried about some prepration H for the hemmmroids your arse will have after 3 days of rocks and bouncing hahahah Beautiful area,bring fishing gear and prepare for possible showers and bears just in case. The last stops for fuel will be Cressmans going up the grade near the top or the Unocal station right in Shaver past dinkey creek road turn off so dont forget to top things off.
Have fun,should be perfect weather.

 

[dbreid]

Update on this. Ran the whole trail (North to South) and it was great! At the very high altitudes the truck's idle ran a little low 500 instead of 600-700RPM, but it was never really an issue. I had two breakages: a Spring eye bolt (rear of front passenger spring in the main eye) and related bushing. I carry a spare of both the bushing and the bolt, so that was no biggie. The other one was that my mechanical fuel pump died. VERY weird, because it seemed to die suddenly, and I had replaced the pump as a part of maintenance about a year ago. I carry a spare electric in line pump, so I spliced that in and ran it right through the stock pump (didn't remove the mech) and was back in action quickly. I haven't had time since getting home to pull the mechnical one and see what actually broke. Maybe the arm bent? Or the diaphragm tore or something...

Trail was snug to say the least. I took on some body damage (already had plenty) and broke my passenger window (accidentally stuck a tree through it...)

But I never pulled winch cable, and never got stuck.

GREAT trail!

-Dan