My dad has a 401 AMC with an edelbrock intake. in a 73 CJ5, someone stole the holly double pumper :mad3: and now I need a new carb:mad: . I was just going to run out and buy another holly, but what are you other guys running? Should I swap to a edelbrock, or another brand? What cfm do you run? My dads old holly was a 750 cfm(????what he thinks it was????)

This jeep is for offroad use only, fuel economy is not important- shit it's a 401:fj: already!

motorcraft 2100 or a qjet. I wouldnt bother with anything else on a rig.

I run MC2100's on both of my jeeps and they run great. My trail junk has a 304 and it runs good. I had a holley and it stalled on hills, I think you can tweak 'em, but I couldn't get mine to work. Get a 2100 from a yard and rebuild it -- about $50 total.

Thanks for the advice, I will check out those motorcraft 2100's tomorrow.:D

Off road? Holley 750 double pumper? in the same sentance? What are you going to use it for? A Motorcraft 2100 is a fine carb, but it's a 2 bbl. It won't go fast like the Holley. If you want speed you need more CFM. If you want to go slow as in off-road/ rocks you want better fuel control, like a motorcraft or Quadrajet. We need to know what you want to giveyou a good recomendation.

Sorry about that, It was gear'd for crawlin only. The jeeps top speed was like 45 with the holly. It is going to be towed to the trails, not driven. My dad use to go to the con, imagrents pass, moab all the time back in the early 80's. That's when he built it up. When he got his new job he didn't have time to go to the trails anymore, so it has been sitting around since 1987. Now that I got my 4runner all built up he is starting to consider getting back in to it. So I want to build up his jeep (a liitle motavation never hurts right!):rasta:

I got the mc2100 on mine and it runs great just put a fuel pressure regulator on so it wont stall on you on the big obsticles :D

Will it mount right on to his edelbrock manifold?
And thank you again for you help guys!:D

you'll have to get a spacer/adapter for it to fit onto the edelbrock manifold the mc2100 is a large bore 2 bbl carb and you will probably have to move the linkage a little for it to get the right pull if I remember corectly

MC2100 is a great carb...like was said above if ya get at extreme angles you'll need a pressure regulator.
I've had mine up to probably 50 degrees both ways and at pretty good off camber angles and it works fine.

Bought mine remanned from Auto Zone for about $170 or so, and put a manul choke on it (mine has exhaust gas choke).

Been running mine for couple of years now no problems.

Should be easy to rebuild as well.
MJ

The only down-side to the MC 2100 is it can't flow enough to keep the 401 happy at 3500+ rpm. They are great for angles though.
The simplest answer would be to get the new Holley Truck Avenger which will bolt on with no mods and is designed to work well offroad. They are ~$380.

newt,

Are you sure about that? Seems like the high-cfm "1.21" would be able to do it. They came on Ford 351's.

i have a q-jet on my AMC 360. you may want to look for one off off a mid to late 70's GM truck or van with a SBC 400 V-8.

matt

Let me qualify my statement. All I know is that my stock re-built 401 w/ MC2100 falls on its face above 3500 rpm. I believe this is primarily because the carb can't supply the fuel&air in the volume needed to make power at 3500+ rpm. I could be wrong. I think the 2100 is a great carb for a 304 or swapped onto a 258, but it can only flow so much. Someone proove me wrong and I'll retract my statement. I've been wrong before.

What vehicles came with the 2100? What should I look for at the wrecking yards. A picture would be helpful.

holy expensive carburator batman:eek: Kragen wants $238.49+ a core charge of $44.40!

And that doesn't include any of the mounting brackets that I need either.:crybaby2:

When you run a pressure regulator with the MC2100 what pressure do you have it adjusted to?

Thanks

The holley avenger will for sure give you the most power and hopefully is as good now that they did some work to get them to work for offroad. I run a holley 390 and did some work to it myself and it wheels pretty dam good but it isn't a q-jet. To get my carb to floud the angles need to be really bad but side hill has never been a problem.

On the street I run my psi at 7 lbs on the regulator. When I get to the good oblticals I turn it down to aout 3. It works for me but other people may run thers differently. I would also like to hear what other people run theirs at.

Originally posted by 66CJdean
The holley avenger will for sure give you the most power and hopefully is as good now that they did some work to get them to work for offroad. I run a holley 390 and did some work to it myself and it wheels pretty dam good but it isn't a q-jet. To get my carb to floud the angles need to be really bad but side hill has never been a problem.


What mods did you do to your 390? I have the same carb on my commando and I want to tweek it a little. Mine loads up a tad on side hills, but the up hills arent a prob.

I have a newly rebuilt 2100 and I can't keep it running. It only runs if you totally gas it - what do ya think it could be? I have no vacuum lines in use except from the manifold to the carb and one from the dist. to the front of the carb. I don't have the choke hooked up and the only fuel line I have is the one from the tank, no return.

I had a holley before (wish I never sold it now) and it ran ok, always ran rich though. Anyway this one won't run at all - looks like someone beat on it though. When you take the top half off the seal surface is shot, like it was beat with a hammer. Only thing I could figure is the fuel from the float was spilling over so you have to really goose it to keep it alive.

I might go try a Qjet but it is really probably something else.. Jeep has a 225 with the petronics ignition conversion, offenhouser hi-rise intake, JC whitney headers. Manifold is made for a 4 barrel but I don't really care wether I run a 2 or 4.

So..

Think I should try another 2100 (can't find one at the PnP) or a Qjet ($15 at the PnP on several different cars. Also is a Qjet a Qjet? Is there something I should be looking for?

The talk has been mostly about the 2100. Has anybody run the larger big brother 2150? Used on 351m and 400 Fords? They are the same carb but with larger venturies and butterflys. May allow enough airflow to support a 401.

Will the MC2100 bolt right up to a stock intake manifold on an AMC 304? I need to replace the carb in my jeep, I'll eventually be doing a engine swap, but I need to be able to wheel this summer.

Can I just go to Advance Auto and ask for a remanned MC2100 Carb, and get the right one to bolt up to my application?

Thanks.

I would run a quadrajet, fed my 400sbc happily at all angles, only ever hicuped on steep hill with heavy bouncing (actually kept running well enough to bounce me onto my lid)

The 2100 are great carbs though and did come on some 360's that I know of, we ran one on my friends 360 CJ-8, choked the motor down at high RPM but its a jeep so we didnt really care about high RPM's.

i've got a Motorcraft off a 80 304 if anyone is intrested.

Originally posted by AlaskaXJ
The talk has been mostly about the 2100. Has anybody run the larger big brother 2150? Used on 351m and 400 Fords? They are the same carb but with larger venturies and butterflys. May allow enough airflow to support a 401.

I'm 99% sure 2150 only means that its got altitute compensation and 2100 doesnt (wierd looking thing on the top of the carb where the air cleaner goes)

my 360 has a 2100, as does my truck, but they are just different versions. the truck is a 2100-a I think (electric feed back, no ported vacuum source... junk) Jeep is a 2100 with something like a 1.28 bore.

Like others have said, run a q jet...but then you need an adapter.

Those motors came stock with a motorcraft 4350 carb...not too shabby off road but junk compared to a quadrajet.

Third option would be a Holley truck avenger...have heard good things about them, but you will not find them as cheap as the other two.

It's all a trade-off. Good luck.

Is the Qjet a standard bolt 4 barrel? My offy intake is made for a 4 barrel

Originally posted by Brandon
Is the Qjet a standard bolt 4 barrel? My offy intake is made for a 4 barrel

They're spread bore Brandon. Easy fix,. take a spread bore to square bore adapter, and turn it over:D

Originally posted by mike


They're spread bore Brandon. Easy fix,. take a spread bore to square bore adapter, and turn it over:D

Thgis is true, however I've heard of some cases where the secondaries will not open fully with this setup. A bit of work with a dremel might be required...this is second hand info, so treat it as such.

Originally posted by Mrlo


Thgis is true, however I've heard of some cases where the secondaries will not open fully with this setup. A bit of work with a dremel might be required...this is second hand info, so treat it as such.

Depends on the adapter you have. I bought a 4 hole and then machined it to fit the primaries and secondaries ;)

what about jet performance thought I seen them selling a rochester q-jet 4 barrel 750 or 800 cfm carb?

Read here: http://www.pirate4x4.com/forum/showthread.php?s=&threadid=116603

So what can be done to a fresh MC 4350 to make it run well off road.

I don't want to swap in a Qjet yet.

Originally posted by Monkeyboy
So what can be done to a fresh MC 4350 to make it run well off road.

I don't want to swap in a Qjet yet.

Not much. Don't get me wrong, it's not a bad carb off road, but it could be better. I ran mine for a year after the rebuild and the damned thing just would not hold an adjustment.
I just did the Qjet swap on my 360 a few weeks ago and have not had the chance to test it on some real hills yet... but, there was a noticable improvement in throttle response, and the carb never loads up, or cuts out under really bumpy conditions like my 4350 used to.:flipoff2:

to run q-jet on and intake jsut get a 1 inch spacer made for the spread bore carb, it will give it enough clearance and will fit the edlebrock intake. my personal choice would be to get hte new truck avenger from holley. its a square bore carb so will bolt right up and if you dad did a lot of tinkering in his day he will be familiar with the holley. i have the holly and my 318 and have very little complaints. i got it when it first came out and had to send it back, but now the bugs are worked out. runs great off road. i did have a q jet and the power is amaxzing compared to it. and it still does great off road.