alternate 2.8 carburetors

[acelcobra]

I have done the duraspark conversion, and made a manual metering block, but I don't feel that I am getting the most out of the stock emissioned carb. I read about using a 7448 Holley and was wondering if there were others available. There seem to be alot of 2 barrel Holley carbs that appear to have the same base as the 7448, but I can't find very much info about their CFM or compatability with the 2.8. Any help would be greatly appreciated. I need this truck running reliably.
Thanx

 

[kimcrwbr1]

A holly 350 with number 050 jets is supposed to work good for the 2.8l or a motorcraft 2150 without feedback venturi 1.08 with 050 jets is also a popular one but the 2.8 is not a powerhouse did you put the adjusting ports on the feedback block closed is rich open is lean

 

[kimcrwbr1]

http://www.therangerstation.com/forums/showthread.php?t=71391&highlight=holly+350
maybe he has more info on the holly I found a motorcraft from a 302 for mine and it works jus fine I did valve guide seals duraspark carb and all new intake manifold gaskets and put the thermostat on the intake manifold going into the radiator with 180 deg stat. Are you sure the timing is right 10 deg no vacuum 20 deg with manifold vac and well over30 deg at 3000 rpm

 

[schmoo]

the 2100 and 2150 carbs are the best available.
people are adapting them to all makes of cars
for mileage and reliable operation
after the original carb can no longer be repaired.
holley is not an improvement unless you really
like working on carbs.

 

[acelcobra]

maybe the 2150 is just out of adjustment. i'll have to try some tweaks this weekend. at one point, i had it running perfect...good throttle response, pulled uphill well, but i tried adjusting it after a vacuum line fell off (before I knew it was a vacuum leak) and now i can't get it back to where I had it. as far as the metering block, i just set the screws at halfway and left it.

 

[kimcrwbr1]

the one for the idle can be closed all the way then adjust air fuel at needles. you might be running too lean try closing the high speed and slowly turn it out as you rev it up to 3500 and see how it changes closed rich open lean it controls air bleed to the venturi booster

 

[schmoo]

thank you K. mine is in a snowbank right now
but i will try that when it gets warmer. my
original valve had just one screw that adjusted
both circuits- it worked good. martin's valve
is better but i haven't been able to make it run
better. the first one i made was in 1/2 inch
clear lucite. big mistake- it cracked all over.
the new one is a brass plug like the old one
but two screws.

 

[kimcrwbr1]

Yea I been talking to a guy that says he has a machinist friend and make one out of aluminum I noticed they do get exposed to fuel so you need a material that resists fuel

 

[ammocj]

Also,
make sure you have all the hose conections from the carb blocked.
I somehow had decided to run a hose from one of the carb nipples to a nipple below the carb on the intake and it never seemed to run quite right.
It would start right up cold and die after a few seconds and even warm seemed very inefficient.
Well, I went back to the Holley I had worked on a lot a while ago but got fed up with. I soaked it, (again) cleaned it (again) hooked it up (again) adjusted it 6 or 7 times (again) put the stock carb back on and plugged all tubes except advance to distributer and night and day. She starts up cold and sits there idling even below zero. Runs hard thru all the gears. I'm finally happy with this motor.
If you really need a Holley to frustrate the hell out of youself then they are out there. I might even sell mine as I doubt I'll ever attempt to use it again.
I might also be in a weird area for tuning carbs (or it's me) but I had an RZ350 years ago I could never get tuned right in this elevation. But you should have seen that thing scream in Florida.

Al

 

[acelcobra]

runs worse now

I'm not sure exactly what I've done to this thing, but it's dogging around awfully. Is there a good base setting to set the 2150's needles, choke, fast idle cam, choke pull-off, and manual metering block? I'm nearly at my wits end with it....so frustrating.
Ammocj....when you blocked off vacuum lines, did that include choke pull-off and pcv? I've got the same ports at the bottom front of carb to spacer (couldn't figure out what it exactly does), never tried to block it off though. Also, I have an automatic trans with a vacuum line to it too, doesn't shift right without it attached.
I appreciate all the help from y'all. This has really got me feeling like an idiot.

 

[Original_Ranger84]

Are you running the old computer controlled carburator? if so get rid of it and get a stripped down standard 2150 carb.

 

[kimcrwbr1]

what kind of spacer do you have between the carb and egr spacer I stumbled into one for a 302 felpro #60529 that fits the base of the 2150 but your using the feedback carb right. I would start off closing the meter block all the way turn the needles 1 1/2 turns out keep the PCV the choke pull off I have two lines going to air pump valves thermactor and bypass but can be plugged if your not using the air pump. did you mess with the egr it is a possible vacuum leak. so basically all you need is the advance from the tree the PCV and the choke pulloff. the choke pulloff comes from the back of the carb and is restrictedjust for the pulloff. I also put a restrictor going to the vapor cannister solenoid from the tree also. OK recap
power valve front bottom of carb to spacer just below it
PCV back of carb to valve (check valve or replace for shits and giggles)
advance from tree to distributor (check timing 10 dbtdc with vacuum plugged)
pulloff obvious
there is a vacuum on the back of the carb spacer that used to go to the vapor purge plug that
plug all others except if you have auto trans check shift solenoid (from tree)
check carb nuts and turn idle stop out I set my choke closed then after it gets hot turn it where it opens all the way get the engine up to temp then drop the idle to about 900 rpm turn the idle needlse in one at a time till it studders then out till smooth if you have a vacuum guageturn them both in 1/4 at a time evenly then back out to get the best idle or when the rpm stops rising then adjust th engine rpm where you want it. You can count you needle adjustments should not be more than 1/2 turn between them. Oh yea make sure you plug the distributor into manifold vacuum before you adjust the carb. The one on the back of the carb spacer can easily be missed and taking a length of vacuum hose put one end up to your ear and listen around all the gaskets and connections can locate a leak just be careful of mooving parts. mine runs best around three turns out on the needles. They are sensitive so make sure you have no vacuum leaks and take your time once you get it dialed in dont try and make it better. Oh yea I have a vacuum going to the heater door on the air filter housing helps to warm it up in the morning it goes to the tree also.

 

[kimcrwbr1]

Once you get the carb adjusted then you can adjust the chokehttp://s984.photobucket.com/albums/ae321/kimcrwbr1/?action=view&current=choke.jpg&newest=1

 

[kimcrwbr1]

oops

hope this helps