1989 jeep yj 4.3l chevy swap questions

[1989gmc]

well i have a few months before ill be able to work on my jeep again so im just tossing different ideas around in my head trying to see what will suit my needs best so i can get a plan going before i get home.

to start off ill explain the situation a little better, i have a 1989 yj that the previous owner swapped in a 304 amc(was the 4.2 from the factory i think). it still has the factory 5 speed (the weak peguot one) and transfer case and axles. it has 4" lift springs and 33" tires for now. the problem came when i blew up the 304 and now i have learned that AMC v8's had issues with oiling system also its not too easy to find a cheap replacement that i trust to last. also the factory wiring harness was all hacked up when the previous owner put in the carburated 304 so there really no going backwards on this one. and if i put another 304 in it i would end up needing a new transmission anyway because it wont last forever behind a v8.

that brings me to were i am now. i really want to get rid of the 304 and the weak transmission. i really like to step up to something that is fuel injected for reliability and gas milage i wouldnt mind getting an auto trans instead. for me the most logical direction is chevy drivetrain because that is what i have always worked on so it is farmiliar. im leaning toward getting a donor s-10 blazer with 4.3l TBI, 700R4 trans, and swapping in a np241c(its free) out of a halfton because it is manual shift so i wont have to figure out pushbutton if the blazer was equipped with it. i choose a blazer because i can pick up a running and driving 1989-1993 ish blazer that should have everything i need for around $500 and if i have the whole thing hopefuly it will make the wireing a little easier.

as i said before most of the wiring on the motor side of the firewall on the jeep is already hacked up from the pevious owner and most of the factory gauges dont work so i already plan on using all aftermarket gauges. i know ill have to deal with rerouting exhaust, making motor mounts, trans crossmsmber, swap out the pedals to get rid of the cluch pedal, new radiator, i plan on using a cable B&M shifter so it takes up the same hole on the floor as is already there.

what i really need help on is deciding if this is the best direction to go? is it difficult to figure out how to tie the wiring together? what will have to do for a fuel pump? will i run into any major issues running this combination? what am i missing? if theres anyone how has done this and what kind of price am i looking at? is this a worth while swap or am i really just wasting my time and money with this one.

if it helps i intend to use the jeep as just an all around cruiser, weekend play toy, back up daily driver, it will see alot of time on the road ans alot of time in the sand, it will see some trails and i try to stay away from mud but im sure it will find me sooner or later.

in the end i understand it wont be 300 horse power but ill be happy just to get it back up and running with a reliable motor and better gas milage. and than once its all in and the bugs are worked out if i ever decide to make it a dedicated off road toy than i can always swap in a 350 if i feel the neeed to.

sorry for the story just trying to get some ideas and opinions thank you in advance for the help!!!

[1989gmc]

keep finding more things as i do resarch. what is the best way to deal with the radiator? do i need a high dollar aluminum one for the v6? i know i can use the stock one because the inlet/outlet are on the wrong sides. any advice or tricks to get one that works right for cheap?

[ovrlnd]

my dad had a 4.3 with a carb swapped into his 87 yj with a 700r4 and 231. the radiator was 4 core replacement (a bit overkill but works great). it has an in line electric fuel pump. wired into the fuse box and 12v ignition on. it runs great, gets awesome mileage and he has been very happy with it for the last 2 years.

[1989gmc]

thanks for the input! does he have any trouble with the inline pump(never used one) it seems like the easies route? i plan on trying to keep it TBI just for the extra reliability and ability to run on angles. also what is better keeping the stock fan or swiching over to electric fans?

[1989gmc]

ok been doing a little more research and im trying to figure out what electric pump anyone else uses? i believe i need around 13-15 psi to properly run a TBI system can any one confirm this? also what gallon per hour sould i be looking for with an electric inline pump?

[ovrlnd]

Originally Posted by 1989gmc

thanks for the input! does he have any trouble with the inline pump(never used one) it seems like the easies route? i plan on trying to keep it TBI just for the extra reliability and ability to run on angles. also what is better keeping the stock fan or swiching over to electric fans?

nope. it's been a while since I have been under it, but iirc it is on the framerail. his has a clutch fan on there and it works fine keeping it cool with the 4 core and no shroud. I have been trying to convert him over to an electric fan setup since I converted over to one.

[1989gmc]

thanks for the help again ovrlnd

[ovrlnd]

Originally Posted by 1989gmc

thanks for the help again ovrlnd

no problem. if you need anything else let me know. I can also get pics for you if you need them.

[1989gmc]

Originally Posted by ovrlnd

no problem. if you need anything else let me know. I can also get pics for you if you need them.

if its not too much to ask can you get a pic of where exactly the motor is set up. i know the 4.3 is shorter than a 350 so i should be able to adjust it some but ill be making my own motor mounts so just want an idea of proper placement

[Haggar]

That sounds right for the fuel pressure. If you are going with an inline pump, just try to keep it low and as close to the tank as possible. They make very nice motors for a Jeep.

*shameless plug*

I have two 4.3 TBI V6s for sale with wiring harnesses. The wiring is pretty simple on those. $200 for the lot (two engines with starters, ps pumps, alternator, flexplate, ECUs, etc..)

[1989gmc]

thank you for the input Jesus . ill make sure to find a good spot to mount the pump! i saw your thread with the 4.3's and was going to write about them but at the moment the project is on hold until i can get home in january that is why as i stated this is more of just a thread to help me with planning the project that when when i do finall get home i can jump right in! if i can find someone that will go pick the stuff up for me before i get hom than ill definatly keep you motors in mind! thanks again


edit. - why does it say Jesus when i type H a g g a r???

[ovrlnd]

no problem. I will snap some next time I go over there.

[Haggar]

Hehehe, just a joke that CC put in with my name..

[1989gmc]

Originally Posted by ovrlnd

no problem. I will snap some next time I go over there.

ok thank you vvery much!

[1989gmc]

well i picked up a blazer so i guess this swap will be underway when i get home. i ended up finding a 1992(i think) 4.3 auto 4x4 for pretty cheap, so i bought it. it should be at my house sometime this week so ill have my dad look it over and hopefully get more info about it since ive never even seen it(or even pics of it for that matter). but the parts gathering has begun. i was wondering if there is anyone out there that has done this and knows about what MPG's to expect when its all finished.. when it gets back on the road itll be on 33's and 4.10 gears to start with. thanks for all the help and keep the info coming

[cclev1967]

will you do me a favor and keep updates on this as you go, im getting a 93 yj with a 4 banger in it, i want to do a 4.3 swap, so ill le tyou go first then you can tell me what you had to do. lol
i would even like to get with you when you get home if you need help and give you a hand, im not a mechanic but i do have common sense and can turn bolts if nothing else. just see how it all goes in and do the same thing to mine.
thanks

[1989gmc]

ill dont get home till january but once i do ill keep the updates coming!

[ovrlnd]

i don't know the exact numbers but my dad drove his yj (carbed 4.3, 700r4, 4.10, 31x10.50) from plymouth to claire on 3/4 of a 15 gallon tank. my brother in law was with him and confirmed it.

[1989gmc]

thats not too bad.. ill roy end up a little better by keeping it TBI from what i hear but i guess i wont know till i get it done.

[insane88yj]

Is it hard to convert the stock harness for tbi set up over to use it or is it easyer to go with the painless herness? I'm not that good with wiring. thaught I'd ask in here reather than start a thred.