c4boom

I need to put a new carb on my 350 the problem is this motor sees grate changes in altitude form sea leval to about 6000 feat. I am looking for a good carb to make torque and starts good in the cold. The motor is a stock 350 out of a 85 truck. thanks ahead of time.

contactpatch

c4',
What kind of choke do you want?
.
altitude --> choke issues

Bunker82

That is a BIG change in altitude. Generally you need to change jets in ANY carb when altitude has changed 2000ft and temperature changes complicate things even more. Your options as I see it are as follows:

1) Get something that corrects for altitude on its own and there are not many options here.
a) Some form of fuel injection and let the computer automatically adjust. This is the most expensive but in your case I think the best option.
b) Put on a computer controlled Q-Jet system. It has the ability to adjust automatically to altitude if I remember correctly.
c) There are some weird smogger Q-Jets that are not computer controlled but had some kind of altitude compensation in them. But I wonder if that would have a range of adjustment to cover 6000ft in elevation changes.

2) Get a mechanical carb that has EASY to change jets and just live with the fact that you will be changing jets a lot. Options include:
a) Edelbrock - Their carbs are quick to change metering rods, takes a matter of seconds. If you have to change jets it takes more time but it isn't all that bad.
b) Holley - Stock Holley's are not quick to change jets on but there are things that make changing jets faster, much faster. Ideally you would keep your eyes peeled on eBay for an electronic fuel bowl made by Holley some years ago. I have seen setups, but they are rare. But you can change "jets" with a turn of the **** from the driver's seat. Holley has quick change bowls that let you just take off two plugs to change the jets, but you will still have to drain the fuel bowl every time. There is the Holley adjust-a-jet I think it is called, but I have heard bad things about it. It uses a big "needle" that you turn to vary the "jet" size. It would only take seconds to adjust. There is the Carb Shop speed blocks that allow you to pull out the jets without taking off the fuel bowl. Or if you want to go in style then look on eBay for Weber Power Plates like I have that allow quick adjustment and more power, but jets are not cheap for them.

Ok there is some ideas Best of luck with it.

c4boom

the fuel injection thing would be nice but i do not have the time to shut this thing down long enough to set that up choke is giong to be electric. any one know if one carb handls altitude beter than the others

five7kid

iTrader: (14)

You already have been given the correct answer:

"b) Put on a computer controlled Q-Jet system. It has the ability to adjust automatically to altitude ..."

No other carb can accomplish that.

SSC

Yea a CC carb like mentiond, if you dont have a CC harness or an electronic distributor get either a #80457-S (Holley) or #1406 (Edelcrap). Either of these carbs will require small amount of tunning to get the mixture nailed down.

c4boom

nope no computer any thin in this thing the cruise works off of vacume

five7kid

iTrader: (14)

I guess I don't understand the premise here.

Why do you need to put a "new carb" on your 350? What's on there now?

Is this 6000' altitude change a daily thing?

Of course your cruise control operates on vacuum. They all do. That doesn't mean it can't be controlled by a computer.

c4boom

it has a stock q jet that has a tone of miles on it and it just dose not seem like it is on the ball any more. The 6000 foot thing is some thing it hits about 1 out of ten times it is out. i was just hopping that in the last 20 years since this carb was made there would be some thing out there that would help it run better and get some better MPG that and the motor is in a very heavy truck like fully loaded over 6 ton.

five7kid

iTrader: (14)

A lot of things have been done with carb technology since GM last made one in 1987. However, for self-adjustment and fuel economy, the CC q-jet is the best choice.

Is the carb on this truck CC?

c4boom

as far as i can see it has no wires or any thing just power to the choke. how hard is it to put a computer controled carb on and how hard is it to tune

five7kid

iTrader: (14)

Guess I asked the question twice. Sorry, didn't look back far enough before I asked again.

Tuning - fairly straight forward.

Installing - pretty involved. It would be just as easy to put on a truck TBI set-up. It would probably make more sense to go TBI. I'm considering doing that on my '84 full-size van which currently has a non-CC carb.