I have a 70 bronco and am currently running a Q jet. The motor is a 347 with performer heads and performer rpm intake. Headers with flomasters. Camshaft .550 in lift.
The carb works well off road but loads up at idle and it seems to bog when the secondaries open up. If I can get those two issues solved I think it will run acceptable.

I would like to haer what size of carb cfm? And the good and bad of the different carbs out there because I don't know jack about them...:confused:

I have heard of the holley truck avenger, the edelbrock off road, and the q-jet that I already have.

I think there is alot more power in my motor but the current carb is holding it back big time.

have you tried running the q-jet backwards yet, there are a few people that say they work a better that way.

If it bogs when teh secondaries open sounds like they need to be adjusted, like tightening the spring up so they don't open as soon.

IMHO the motorcraft 2100 is the best offroad carb but it won't work in your application. every time i flopped my 83 on it's side i had to cut the motor off

Sounds like you need something in the 650-700 double pumper range. Forget the vacuum secondary carburetors with that large of a cam lobe, you're probably going to need mechanical secondaries.

Put in extended vent whistles and some offroad needles and seats. Also, drop the float levels a little bit and you should be OK. I did that to my GPW's 650 DP and to the Bronco's 750 DP and they operate pretty well.


Q-jets were never really intended as performance carbs anyways so bogging is what you get when you're running Aluminum heads and (my guess) an X303 camshaft.

yep, motocraft 2bbl, there is nothing better offroad.
I've seen a a vew chevy guys run Q-jet's, and they work decent, but seem to HATE hitting bumps with speed, especialy on hill climbs, that and the usual tuning issues with them..

My one housemate has a carter AFB on his rig, total garbage. nice flat spot off idle, and floods and bogs just LOOKING at a hill

Four of the guys in our club run edlebrocks.

One is on a 429, and it works "ok" but it's just a mud truck, so no expirance on angles, he also hate holleys with a passion.

The second is on a built 400, the carb was on the motor when he got it, and the guy who built he motor, seemed to know what he was doing, so the motor runs pretty well, but again, a mud truck, so no angles.

The third is on a 302, used to run like total ass, but after a ton of tuning, it now starts in less than ten seconds of cranking, and it no longer pours black smoke.. Still sucks on angles, and is rather gutless.

The fourth is on a stock 400. Hates anything that ressembles a hill, bogs when you get on it. Total opposite of the 2100 that was on the old motor.

Quite a few of us run holleys, myself included. Plane jane 4160's.
I like them because they are so simple to setup, bolt them on, adjust the idle screws, and maybe the floats, and any tuning from there is pretty simple as well..

Wheeling I've never had any issues, with it, I'll roll my truck over before the carb floods. when it's 10 below, it starts with two pumps of the gas, and 1/2 a revolution of the motor. Plus the throttle response, and fuel mileage of them seems to be alot better compared to edlebogs..

The only issue I've seen with holleys ,is the floatbowls can pour into the carb if you really stand them on end(like 70 degre incline) but putting a line between the vent holes.


I've heard nothing but good about the TA carbs, but for the money, I wouldn't buy one, when you can set a regular holley just the same for next to nothing.
Plus when you start talking about a $400 carb, you at the same price as efi...


My vote is a 4160, cheap, simple, and flat out works.

Honestly I would look at grabbing an intake, harness and ecu from a mass air mustang. There really is nothing better offroad and it will cost you the same as a new TA. But as far as carbs, an edelbrock is the same thing as an AFB, almost identical inside. I have ran both and both totally suck balls. They arent bad for a street carb and have good response but suck for everything else. I had issues with 4150's on my '78 400 bogging and dying on really steep climbs and side hills, but I switched to a 650cfm 4160 and it seems to be much much better. The motor has alot better response now as well.

After I set the idle mix correctly. the 670 Truck Avenger I have runs great. We have had the truck almost verticle, to the point where all my wieght was on the back of the seat. It wouldn't idle but just a little gas kept it running. and after my son flipped it on its side it was still chugging long enough for me to keep telling my son to shut it down. after being on its side for over a hour it fired up imediatly. I was very surprised how well it worked. Everyone kept telling me I made a mistake and should have bought a Q-Jet. But I like the TA just fine.
My engine:
390 (396 cid) FE with Edelbrock Perf RPM heads, intake and cam (232@0.050 and 0.572 lift).

Switch to SEFI, your motor will really come to life when you do. You've already spent the money to build a high zoot motor, may as well drop the $1500 or so to convert it properly, and have a super bitchin setup.

A Q-jet is about as good as it gets when it comes to off road carbs. I have been through it with the Edelbrock/Carters, never had any luck with the Holley, and the 2100 is still a good ole' standby, it never lets me down.

I'm running a Q-jet pointed forward, and it does well, but I'm not a full throttle kind of driver, so stalls are pretty infrequent. I haven't tried turning it around to see if it works better or not.

I'm in the air whether I want to convert my motor to SEFI or 'pane. I'm leaning toward propane just for the simplicity.

Run the 'pane. 100 octane minimum and the driveability makes fuel injection jealous. It's really all about tank mounting and having enough fuel capacity to do what you need. If you can't carry enough fuel there are emergency bbq adapters available so you never get stranded.

search aorund on the net for qjet tuning articles...with that cam and build any carb you run will have to be tuned...i dont feel like explaining every detail of q-jet tuning on here, but when you get that qjet dialed in perfectly you will love it

propane really is the best set up. i got my whole system for about $350 and i'm gonna run 3 10 gallon tanks so that i don't have to worry about not having enough for a trip. you could prolly sell that q jet to cover a lot of the expense

The only issue I've seen with holleys ,is the floatbowls can pour into the carb if you really stand them on end(like 70 degre incline) but putting a line between the vent holes.


the motor should be eating a ton of extra fuel long before the fuel spills from the vent tubes.
if that were the only issue it would be solved with vent tube extensions.
the problem is when the angle gets high enough to raisde the float level higher then the main discharge nozzle.
it begins to gravity feed rather then be drawn by vacuum signal.
if you can keep your foot in it the motor will pass the excess fuel, but if you have to lift it will flood.

i've got the truck avenger onmy fresh 400 and all i had to do was set the flote and idel and it runs like a top.

ps.jegs has the ta for 345. http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=20837

but you can call summit and they will beat it by 10%, and shipping and handling is cheaper, and they give you 20$ in summit bucks

Ford 2v(2100) by far the simplest to rebuild or work on and flawless performance once the float is set (low) That being said, they are fairly limited for CFM, so probably not for peeps that do lots of throttle wheeling. Anybody try an Autolite 4100?? They are basically two 2100 carbs put back to back and the larger more common one will flow 600cfm I believe. Also I can personally attest that the Predator carb will take a hell of a pounding and keep on going but dont know about it's angle abilities.

efi it! i got mine off ebay complete harneses, fuel rail, injectors, sensors, intake manifold, throttle body & computer for $145 with shipping!
however for your q-jet check out this link:
http://www.florida4x4.com/tech/quadrajet/
:smokin:

Sounds like you need something in the 650-700 double pumper range. Forget the vacuum secondary carburetors with that large of a cam lobe, you're probably going to need mechanical secondaries.





no sir. vacuum secondaries work just fine off road, and that size engine. double pumpers are nice for the street.



Q-jets were never really intended as performance carbs anyways so bogging is what you get when you're running Aluminum heads and (my guess) an X303 camshaft.



:rolleyes:
people who dont know the potential of a Qjet say this. Or, people who run a worn out Qjet say this. My carb guy can make more power out of a Qjet than an a holley of comparable size.

and the bogging is a tuning issue.

listen, i would stay with a Qjet. you have the manifold already, and im TELLING you, if i had a spreadbore intake on my truck i would run a Qjet. i run a truck avenger 670 that was tweaked by Alan my carb GURU.

just bolting my carb back on after i got it back from him (could only make 180 hp, cause secondaries wouldnt open) got me 351/473 hp/tq after he tweaked it. this was a carb that was practicly brand new!

we had put a 650 double pumper on it to make sure it was a carb issue not anything else. the DP only put out 310/390.



204/214 .484/.510 lift is whats in mine. :rolleyes: the carb is so smooth you cant even feel or hear the secondaries open up. it will boil the tires....its called torque on command.

i cant say it enough. keep what you have, send it to me, Alan will rebuild it for you, and you wont be dissapointed.

Stay with the Qjet and find someone who knows WTF they are doing and have them build it. Too many "carb guys" out there that dont really know jack about a Qjet. Find one that does and you will love it. Backwards Qjet = Arkansas EFI

propane really is the best set up. i got my whole system for about $350 and i'm gonna run 3 10 gallon tanks so that i don't have to worry about not having enough for a trip. you could prolly sell that q jet to cover a lot of the expense

uhh please tell me where such a purchase can be made!

i got mine off ebay, a used kit. i didnt find any right now, but there is usually some. if you are wanting new stuff look at this...
http://cgi.ebay.com/ebaymotors/LPG-PROPANE-IMPCO-425-MIXER-CARBURETOR-KIT-STYLE-D_W0QQitemZ270182729125QQcmdZViewItemQQptZMotors_C ar_Truck_Parts_Accessories?_trksid=p4506.m20.l1116
all you would need to add is a holley dbl pmpr base plate hoses and tanks.

uhh please tell me where such a purchase can be made!

you realize that price is a few years old now, right? 2006?

yeah after i posted... but still... what is 350 plus 3 yrs inflation?

under a grand for sure!

man ppl have diffrent opinions on carbs. it seems to me Q jet ppl and holley ppl dont get along!!!Edel junk is the same as a thermoquad thay are a pain to tune(trust me im mopar and thats wut mopar comes with) I like holleys its wut i know, its wut i got parts for. To me thay are simple. Just make a transfer tube for the holley and your good...if you dont every hard bump will stall you out. Get good FILTERS you must run a good fuel filter!!! the holleys hate dirt! i run a tractor filter with a water seperator and never had a prob since. I never gave q jets a try because alot of race ppl told me not to fuck with them. IF you want a holley cheep ill sell you a 3310 770 vacume sec. with down leg bosters for 50$ this carb is a factory 68 454 carb...im not a carb person i just know allot of ppl that are and helped me out...if you run a 4bbl for a dd you learn fast. Its all about wut you are doing with the truck. Read about each type of carb first and see wut you can handel as far as tuning and buying parts. To fine tune youl neet shit like jets,pump cams,squerters,powervalves, medering rods,medering blocks,medering plates,Venturi Booster,air bleeders.. on and on and on bla bla bla.... hope i helped

you helped me consider suicide trying to read your fawking-mis-spelled-no-punctuation-run-on-o-rama :flipoff2:

you helped me consider suicide trying to read your fawking-mis-spelled-no-punctuation-run-on-o-rama :flipoff2:

That's not the Pirate way... You KNOW you've got to start encouraging the brainless/techless one to either fawk a blender, or throw himself into a woodchipper :flipoff2:









PS: If you do decide to be a poon, and kill yourself, do it right the first time. Transporting screwups to the local nut house (and the resulting paperwork that goes along with it) is a pain in my ass....:eek:





PPS: If you do manage to get it right, I put dibs on your truck :flipoff2:

you helped me consider suicide trying to read your fawking-mis-spelled-no-punctuation-run-on-o-rama :flipoff2:

ha thats good! i forgot to edit before hitting the go buton:shaking::flipoff2: my hyper ass tryin to type ant working any more.

ha thats good! i forgot to edit before hitting the go buton:shaking::flipoff2: my hyper ass tryin to type ant working any more.

Then quit letting your inner moron show, go back and edit that shit already.... :flipoff2: