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Discussion Starter · #1 ·
Guys...Im new to this forum but looking forward to getting back to my Jeep project. I have a 81 CJ5 w/ a 4.3 Chev-turbo 350-Dana 300. Originaly had the 151 but it blew and I replaced it w/ the 4.3. I used a stock 1985 manifold that used a quadrajet and heard that quadrajets could handle hills/articulation well. The joker I had rebuild one for me sold me junk...lesson learned. Im now back to the drawing board and would like suggestions on a good card to use. I dont want to go EFI as I want to avoid the electronics and keep it simple.
I see Holley is making an off road 4 barrel 470 CFM (Avenger) and was wondering if you guys have had any experience with them? If not, what brand/type would you suggest.
Its a play vehicle, drive to work in summer's here in OR but take it wheeling in the winter.
 

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Don't discount the simplicity of fuel injection. Also, if you assemble the system yourself you can lower the costs to the same as a carb. If you're not doing your own work on the Jeep, it's high time to learn... otherwise you'll never be able to afford to keep it on the road or the trail.

Why not start by rebuilding the carb you've got with an inexpensive rebuild kit? If you rebuild it, you know what you've got, who did the work, how it was done and where to go if you need warranty work. The benefit is that no one can take away the knowledge you gain... and this is a HUGE plus when you're on the trail and something fails.
 
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Discussion Starter · #3 ·
I agree that fuel injection isnt that complicated and it doesnt intimidate me to covert. My issue is I have a laundry list of things to do to get it on the road by next summer (rewire whole jeep, disassemble and paint) and want to go simple for now and in time I will go injected. For now the KISS methodology is what im after.

BTW....Im a father of 3 boys w/ 6 acres of land to tend to! Free time for Dads projects is at a premium.

When I converted the 4cyl 151 to a Chev 4.3 I didnt have a carb to rebuild and was steered towards a quadrajet. The carb I had built for it never ran right (no idle, backfire, etc and the guy wouldnt fix it) I put my old Edelbrock 600 on it from my Mustang and it ran great, but its too big and can 4 wheel worth beans. Thats why Im back to the drawing board and was hoping for some suggestions. I see many references to tme MC 2100. Does it handle off camber well?
 
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Discussion Starter · #4 ·
I agree with Leve on the FI.....
My question is...what happened to the electroncs that came with the 4.3?

Truth is, FI is actually a lot easier....I just completed a SBC swap of a TBI into my 84 CJ...the FI was the least of my problems....Hooked up maybe 6 wires at most...and I have a computer to tell me what if anything is wrong....

You will NEVER be able to get a carb to handle hills as well as FI can....When it is all said and done, I think you will end up spending twice as much time trying to get a carb to work vs leaving the engine in it's original FI setup.

BTW....I think a Qjet is too much carb for a 4.3....
 
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Discussion Starter · #5 ·
I bought a rebuilt long block 4.3 and went to the junk yard for parts (valve covers, intake/exhaust manifolds, pulleys, etc). What Im up against is this is one of the last years ('85) of the non-vortec 4.3. Everything changed with the Vortec and Im leary of piecing together an older FI unit.

It might be something I'll have to work into the winter project.

With that said, what kind of FI would you suggest....try to get a complete FI unit off an older car? If so, just replace the injectors??
 
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Discussion Starter · #6 ·
Go find a 4.3 with FI...chances are the block has not changed much if at all...
Take it all...

Or...buy the Howell FI setup....basically, it's a bolt on GM TBI
 

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So you found a 4 barrel intake for a 4.3 in the junkyard?? Or are you using an adapter? It will take some searching to find a good complete harness and all the sensors to put the GM factory FI onto that 4.3.

Here's three carb options as I see it:

1- Find a circle track race shop or off road place near you and have them point you in the direction of the local carb guru. This is often a guy who works at one of these speed shops and does carb work on the side or does it out of his garage at home. Take the carb to him and tell him exactly how you want it to behave. He will make your cabr work or offer a different solution.

2- Search on here for MC2100 2 barrel, there has been quite a bit of talk about them lately as far as the 4.2 swap goes. I would think that you could get one to work very well on a 4.3 too. They are simple and with the right adjustments (you can do yourself with the info you find searching), they work great offroad, idle smooth, and have great throttle response.

3- If you do indeed have a four barrel intake, I am thinking around 390 cfm would be a good fit for that engine. Again, find the local carb guru and have him get you going in the right direction.
 
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Discussion Starter · #9 ·
Jdogg...thanks for the input.

Yes, I found a 4 barrel intake at the junkyard. It came stock on '85 Astros and is set up for a quadrajet. Im sure I could round up all of parts but I dont really want all the sensors and bull on my motor. I like it simple.
If I go with FI it will probably be something like the Holley TBI (http://www.holley.com/502-20S.asp)

As for carbs I appreciate your suggestions. I originally was looking for a 2 barrel intake but couldnt locate one. The 4.3 was used very speratically (monte carlos, el caminos, silverados, astros, blazers, etc) so it was hard to do research.

You mentioned a 390 CFM carb....but what kind? I would go the MC2100 route but my manaifold is 4 barrel. Im assuming they have an adapter for a 2 barrel to fit on a 4 barrel manifold?

Thanks again
 

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[ QUOTE ]

If I go with FI it will probably be something like the Holley TBI (http://www.holley.com/502-20S.asp)

[/ QUOTE ]

There are much better FI systems than the Holley (all others are better). It works most of the time but never is quite right and requires constant adjustment. If it is cool in the morning and hot in the afternoon, it has to be adjusted for example.
 

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Ok so you do have a four barrel intake. I don't remember ever seeing one. GM must have made a small Q-jet to fit them. If you can find a guy at the parts store that will look up that specific carb application, you may find that a rebuilt or new replacement isn't too awfully expensive. Or maybe you can get some tag or part numbers to compare back at the junkyard.

390 is a small Holley carb. Holleys are notorius for not running worth a crap on incline. That being said I have a friend who had the local "carb guru" tune his after explaining whathe wanted it to do and it has worked flawlessly for four plus years. Knowing this. I probably would still stay away from Holley unless you find someone who will gaurantee they can get it to run well foor you.
 

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i vote GM TBI, especially if you drive it on the street, and plan on keepin it a while as the EPA will eventually be involved in all our mods

so depending on what year the block is, you can expect at some point it will need to be set up to the emmisions spec of that year

besides, the 4.3 was an ok motor till it got injected, then it became a very good motor

and are you saying ya cant find any of the millions of blazers, montes, silverados, etc that were produced back then, gosh, ya cant hardly walk thru a junkyard round here w/o trippin over them/ubbthreads/images/graemlins/grin.gif, course the motors have probably long scince been melted down cause no one wants a carb motor anymore....

good luck, always nice to hear from an old CJ owner/ubbthreads/images/graemlins/cool.gif
 
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