1989 3.9 v6 TBI to Carb swap?
#1
1989 3.9 v6 TBI to Carb swap?
Im debating on switching to a 2bbl carb from TBI, is this possible? Or would it be a royal Pain and end up breaking stuff from more/less fuel? Id rather have Carb for the extra tweak-abilty. Is this a bad/good idea? I would be able to remove the computer out too correct?
Last edited by 89Dakota_Kid; 06-30-2012 at 09:58 PM.
#3
I've been running my '91 3.9 5-speed carbed since march, the TBI manifold works fine although it does act like a large open-plenum carb spacer and I would've cut it down a bit if I still had access to a milling machine.
The TBI hole pattern doesn't match anything else, I just drilled and tapped four holes and mounted a Rochester-Holley 2BBL adapter because I was going with a Motorcraft 2150
A stand-alone ignition is pretty straightforward with off the shelf parts, same story with a voltage regulator.
I strongly recommend a return style fuel pressure regulator and a safety switch, and I made this all work with minimal cuts/splices to the factory wiring.
Just lost 20 min trying to insert a pic, willing to try again later
The TBI hole pattern doesn't match anything else, I just drilled and tapped four holes and mounted a Rochester-Holley 2BBL adapter because I was going with a Motorcraft 2150
A stand-alone ignition is pretty straightforward with off the shelf parts, same story with a voltage regulator.
I strongly recommend a return style fuel pressure regulator and a safety switch, and I made this all work with minimal cuts/splices to the factory wiring.
Just lost 20 min trying to insert a pic, willing to try again later
#4
#5
A stock late '70s 318 vacuum advance ( non lean burn) distributor drops in, just install a /6 reluctor, it'll fire a wide variety of stuff but I've been very happy running a 4-pin HEI module and the stock coil. Our distributor cap fits fine if you can dremel
I'm 'frugal' but sometimes that's self-defeating, stay away from cardone rebuilds, the lower up-front cost buys you a bunch of aggravation getting it dialed-in...
I'm running a Jeep 304 spec 1.21/351 CFM MC 2150, the jetting is lean enough for decent daily performance and she loves to roll out on the four-lane, my mileage might be a bit better if I'd held out for the 1.08/287 CFM unit I was originally looking for though.
You're definitely going to be overcarbed much past a 350 CFM 2-barrel...
I'm 'frugal' but sometimes that's self-defeating, stay away from cardone rebuilds, the lower up-front cost buys you a bunch of aggravation getting it dialed-in...
I'm running a Jeep 304 spec 1.21/351 CFM MC 2150, the jetting is lean enough for decent daily performance and she loves to roll out on the four-lane, my mileage might be a bit better if I'd held out for the 1.08/287 CFM unit I was originally looking for though.
You're definitely going to be overcarbed much past a 350 CFM 2-barrel...
Last edited by gezn2; 07-01-2012 at 08:33 AM. Reason: added info
#6
gotcha, so I would need to grab a complete ignition system too the correct? What would you all recomend? id like a well known brand like MSD if that's possible. What is the top CFM you would reccomend for this motor? id like to squeeze the most power i can out of it.
#7
I'm sure that's great advice but it was to a 10+ year old question. Guessing he might of tried something else.
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#8
Have you actually done this?
The slant 6 is a even fire motor, being the reluctor is set at 120 degrees .....
The 3.9 V6 is a odd fire motor, with the reluctor set at 112 and 128 degrees.
A long time ago, mopar offered a distributor for this purpose, but it has long since been discontinued.
#9
Me personally, I'm very excited to see that other people are starting to catch on with this idea again.
I've been looking to do this with my 88, a little bit less of a headache getting parts, easier to diagnose, all around just more user-friendly.
Might be a good time to do that, seeing as though the bearings in the bottom end have finally let out this past April.
I've been looking to do this with my 88, a little bit less of a headache getting parts, easier to diagnose, all around just more user-friendly.
Might be a good time to do that, seeing as though the bearings in the bottom end have finally let out this past April.
#10
Proof
I was talking back and forth with this guy in an FB 1st gen group with a 3.9L swapped Colt Wagon with a 4 barrel intake manifold. Turns out he used a small block electronic distributor with a slant 6 reluctor wheel and it runs beautifully. Driving it for 2 years without a hitch.
I've been searching for a long time for video proof of this set up running and i finally got it. Its extremely exciting for me to have finally found videos of it running like this.
I've been searching for a long time for video proof of this set up running and i finally got it. Its extremely exciting for me to have finally found videos of it running like this.
Last edited by Toast9758; 04-03-2023 at 12:02 PM.