'83 J10: 258 Head Swap w/ 4.0+EFI *now with gen. pics

[Sakker]

My 83 J10 w/ 258 is a lil underpowered, and I'm not able/interested in swapping to a 360 or a 401 anytime soon. So I have the opportunity to put on the 4.0l HO heads, and possible the fuel injection with it. I was looking at a Motorcraft 2150 before, but opportunity has come a knocking w/EFI.
I was planning on this J10 to be a DD by summer, but my old car crapped out on me, so I needed to rush to get something else, picked up a nice GMC Jimmy, so the J10 will no longer eligible for DD status.

So I was hoping to hear from anyone that has done this, or anyone that has put in fuel injection. I know that the common thing is to put a 360 or something in, and go from there. I would love to just build up my 258, it only has 32k so I'm hoping its healthy, it ran decent in the fall, needs to new belts and exhaust, but didn't seem to have any other problems.

There will be pictures of the J10 in this thread, and there will be <hopefully> pics of the swap.

Any other suggestions for power upgrades, besides engine swap please? I'm planning 3.73 gears, along with 6" BJ's lift, 35's, couple other goodies to come later. J10 will be used for common trails, and a lil mud :P.

Thanks in advance?

[Kali]

I think you will want to go with 4.10s or 4.56s depending on how powerful you make your 258. I would go with 4.10s at least, that puts you back in the factory power range. I would think a 258 powered J10 would be a real dog with 3.73s and 35s.

There are a number of 4.0 head swap write ups on here and across the net. It seems fairly straight forward but some people run into issues. The EFI I believe is more complicated because fitting it into the bay is a hassle, but there are ways around it.

[edit]
I have 4.10s and 31s with my 258. Only mods on the 258 that I know of is the HEI, MC2100, and 2" exhaust all the way back, no cat. You can take it for a spin and see how much of a difference good gearing can make. I dont consider my truck fast or powerful, but it takes off pretty fast because of the gearing.

[Sakker]

Well now that this isn't going to be a DD I may up it to 4.10s, hadn't thought of that. I saw a multitude of 4.0 head swaps, but not much including the efi.





Got to love mechanics.




Got to love how oil preserves things.

[Kali]

Wow, that truck was very close to being added to the collection here. My dad spotted it on the way home from my sister's house. He came home and told me about it and we were going to check it out but never got back up there. I wasnt too interested in another 258 anyway

Looks like a nice truck though, a lot nicer than described.

[Blue & Gray]

Thought about it also

I haven't really seen much written about swapping in EFI either. There is a stand alone kit sold by Mopar but it's high as gas prices. I have been thinking about more and more, I see a alot of H.O. head sixes at Pull-a-part with the entire mess still together. There's a sensor with pickups on the flywheel and other stuff going on with the conversion, a higher pressure pump etc. There's other options that in the end may cost more but give good performance also. Lots of folks run the weber 2 barrels and like them, there's Howell Throttle Body Injection, based on the chevy 4.3 set up. The EFI is sweet but if it was an easy deal I think there would be a million right ups telling just how it goes off.

[Sakker]

Ya, from what I have been told changing the heads is the hardest part. I have a friend who did on his XJ, his brother helped him, and he is the man who is hopefully selling me the parts. I will be doing the head swap probably on my spring break. The EFI will be put on when I have more time. I'll be nice and put up a guide after I figure out what I am doing.

[tj10]

There is a site called cjoffroad or something to that nature that has a ton of info on wiring the mopar mpi up to work on the 258. I attempted this once with a obd2 system trust me stay away from the obd2 crap. When i get the time i want to swap my 4.0 from carb to mpi if you can get a harness from a yj which is obd1 it is a ton easier. They claim there are only 5 wires that need to be spliced to run the motor. Good luck and keep us posted. BTW if it seems like to much dont be afraid to run a carb im running a new (not rebuilt) motorcraft 2100 with a electric fuel pump and this is the best running, starting and driving carbed vehicle ive driven the mc2100 is close to efi in my opinion im just greedy and feel like i need about 15 or so more hp lol.

[tgreese]

There is a site called cjoffroad or something to that nature that has a ton of info on wiring the mopar mpi up to work on the 258. I attempted this once with a obd2 system trust me stay away from the obd2 crap. When i get the time i want to swap my 4.0 from carb to mpi if you can get a harness from a yj which is obd1 it is a ton easier. They claim there are only 5 wires that need to be spliced to run the motor. Good luck and keep us posted. BTW if it seems like to much dont be afraid to run a carb im running a new (not rebuilt) motorcraft 2100 with a electric fuel pump and this is the best running, starting and driving carbed vehicle ive driven the mc2100 is close to efi in my opinion im just greedy and feel like i need about 15 or so more hp lol.

CJ-offroad has been off-line for a while. There are some mentions of it being up and down on other forums, but I have not been able to get to the site for months.

Another good source for Moper MPI info is jeepstrokers.com - this is the forum equivalent of the old Strokers Yahoo forum.

[jaber]

You can also have the GM 7477 TBI computer modified to "batch fire" and use it to run all the electronics on the EFI...

I have not gotten this far yet, but depending on what info I find and how hard it is to convert, I am keeping this option open...

[Heavy_Metal_Thunder_81]

*01-15-2008, 08:45 PM*
Holy thread revival batman!

[jaber]

*01-15-2008, 08:45 PM*
Holy thread revival batman!

LOL, Some times I dont pay any attention to that.

[Cecil14]

How do people even find threads this old to revive?

You can also have the GM 7477 TBI computer modified to "batch fire" and use it to run all the electronics on the EFI...

I have not gotten this far yet, but depending on what info I find and how hard it is to convert, I am keeping this option open...

I can see absolutely no purpose in using a GM TBI setup on a the Jeep I6s...there is a factory MPFI setup available...TBI is a BIG step backwards in technology there.


aa

[lycanthrope]

How do people even find threads this old to revive?

search function


but to me it says they are doing their part to search first, post second. and also that they're a noob for bringing it back to life.

[Cecil14]

search function


but to me it says they are doing their part to search first, post second. and also that they're a noob for bringing it back to life.

Sarcasm...but I agree it is nice to see someone searching through the old threads. Bringing them back isn't necessarily bad, but tacking onto it without watching the age maybe....


aa

[tgreese]

Yes, better to start a new thread and link to the old thread, if it contains relevant info. But newbs are shy about starting new threads... so it happens.

Not a big deal, generally.