Convert 4.3L Chevy V6 to carb?

Intake manifold:

Carburetor: or 390 or 465CFM

Distributor:

This should get you running. Whatever carb you use, you will need to do some tuning, so I would recommend the Holley, but it is personal preference. The large changes in elevation can't be compensated for by a carb, so you may want to look in to one of the quick change jet kits for the Holley, which will let you swap jets without removing the fuel bowl.

Chris

Isn't there an issue with Holley carbs and incline or off camber stalls?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>

I am thinking that by the time you get done paying for a distributor, carburetor and manifold, you will be over the cost of the Howell wiring harness. I can understand your desire not to have a computer in the vehicle, but really, they do make it run better, cleaner, more efficiently and from 2,000 feet to 9,000 feet without a hitch. Maybe the Painless harness is cheaper, I haven't checked the price, and maybe you can figure out how to use the harness from the donor vehicle.

Earle

Actually it will run, but you will lose power the farther up you go. The air is thinner and requires less fuel to maintain the correct mixture. Having "extra" power to begin with, if there is such a thing, will make the altitude transition less painful, and a jet change would probably not be necessary.

Let me recommend one more thing here. I haven't followed this whole thread as I have been in the Philippines for an extended stay with my now fiancée, but that's another story, LOL. Anyway, you may want to see if you can get the wiring harness to go with this particular engine you have. The cost of doing the carb swap is going to run quite a bit. You will also need to factor in money for plumbing the fuel, probably plug wires, air cleaner, etc.

By getting a take out harness, you can look in to a book published by a company called Jags That Run. This company specializes in Chevy swaps into several vehicles, and also has a book on doing the wiring for the EFI swap. I used their book for my S10 350 conversion, and I have to say it was a very well thought out and detailed swap book. It included every part number for any part I needed, and anything that needed to be fabricated, which really was just the motor mounts, had detailed blueprints in the book. If the EFI swap book is half as good as the engine swap book, the process will be quite simple. I did the swap according to their manual, and admittedly, I had everything purchased ahead of time other than radiator hoses, but they were specified in the book as well. The swap only took two 8 hour days for me and my friend to complete and have a running truck again. This included removing the original engine and transmission.

Anyway, give it a look at

Chris

In some cases there can be. Holley has actually come out with some new carbs especially for off road vehicles which have some features to help the problems. The biggest problem is flooding caused by poor fuel control in the float bowl and fuel splashing out of the bowl vent tube. This has been improved on their new Avenger off road carbs. You can see the details on the carb at

This would be a good carb for this particular swap. Probably better than the

2 Holleys I originally recommended. Thanks for pointing that out.

Chris

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Excellent point. As long as I can find a good running engine which doesn't need the EFI and elec. ignition rebuilt/replaced. If I have to pay to have those parts rebuilt, plus get the wiring harness, plus pay someone to program/adjust the computer, then the new/swap parts may be about the same price.

Guess I need to start look> Ditto.

My brother has a 4.3 vortec w/25000 miles on it, computer and it's fuel injected... So if we were wanting to convert it to a carb setup all he would need is a new intake manifold, carburetor, and distributor?

Troy

I'm usually the one asking the questions, but this time I'll try and answer from 2nd hand knowledge:

Yes, that is correct, as far as the major parts go. Sounds like you'll also need some m> My brother has a 4.3 vortec w/25000 miles on it, computer and it's fuel > injected...

Junk yards around here were mostly that, junk. Just got back from 6 of them, and all engines were missing parts (usually the distributor) and all had over 100k, and none had been tested. Most didn't even know what year they were or what they came out of, or even if they were stollen or not (I imagine since they didn't have any history on them).

HOWEVER, found an awsome place (technicly a junk yard still) called New Way Auto Parts. Several nice engines to choose from. Most are 2001. One 2001 with 28k miles, multi-port FI (MFI?), $550. One 2005 with 11k miles from Silverado 1/2 Ton, $700. They had all been stripped of the computer, starter, and alternator. The guy said he could throw in the computer, and that it didn't matter if it matched the engine because they always had to be reprogrammed anyway. Or I could wait until they got one that hadn't been processed yet, and he would leave everything together (matched set) for me. I think I'll do that because they charge a lot for the starters and other "small" parts when you buy them alone.

They all came from vehicles with auto trannys though, so I'd need to get clutch parts and a flywheel I th> Buy a wreck for less than the engine at most bone yards.

Why not go whole hog and do the Motorcar - Horse conversion I hear it's much cheaper and saves gas to boot.

Seriously, is there one valid reason why anyone needs to get the computer out of their car?

For sure!

I have dumped the computer out of my CJ7 and have looked into retrofitting a points style distributor. I found it was cheaper to just have a spare ignition module and coil pickup than the new distributor so I 'have to' carry the extra electronic parts with me always.

I have a mechanical fuel pump, but can 'easily' gravity feed my carb if I say took out the gas tank or the fuel line on a rock. (been there, done that with a jerry can on the hood) You can't do that with electronic injection....

I wheel in the deep Canadian bush and if the electronics let the smoke out, it is about 75 miles to walk for parts...

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Sounds like you would be better off with a horse as well Mike... The same ridiculous argument you're using for justification also works as an argument against having a motor vehicle at all.

The horse has no gas tank to worry about, uses road side vegetation for fuel and even steers itself when you get whacked in the head by a passing branch.

I'm asking for a reasonable, realistic, reason why anyone should want remove the tried and tested GM TBI fuel injection system off a 4.3 to replace it with the antiquated, FAR MORE complex, finicky, hard to tune rube Goldberg device we call a carburetor.

Of course I suspect the reason has more to do with old dogs not wanting to learn new tricks, than anything else.

What is ridiculous about wanting to be able to fix what you drive or to be able to limp it home if need?

I wouldn't know how to fix him if he broke either...

All of the above were good reasons, plus power, better gas mileage, ability to fix and make run under the worst of conditions and no damn computer to really screw things up.

Sorry if 'old fashioned' mechanical things scare you. Some of us still know how to work on them and fix them.

The computerized system is put in as a compromise. It costs you in gas mileage and power in exchange for little to no user serviceable parts to tune up.

Great for some people with lots of money to just change parts that don't work, but I don't mind actually doing a tune up or fixing things....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

I have never had any trouble with fuel injection components, including the computer, except for my 1977 Bug, which ate some hoses, due to age, and had a pump failure, due to rust in the fuel tank. I have, on the other hand, taken apart far too many carburetors for one human lifetime, and became thoroughly sick of the exercise. What you say about mileage and power is just plain false. FI computers let the manufacturers dial in the precise fuel requirements for far more sets of operating parameters than any carburetor can account for. They also let them meet emissions requirements, by replacing a whole raft of late seventies and eighties Rube Goldberg style cheap plastic devices, that never worked in the first place.

Computers, good. Carburetors, bad.

Earle