EFI 5.0 into 1990 B2600i 4x4 Q's

Well it seems that this is a popular swap & I have done a lot of research but the topics that I read did not answer any of my questions. Before you refer me to a ranger forums, I have been there and the ranger wire harness if different from the Mazda wire harness. Ok so I have a 5.0 out of a 2000 Mercury Mountaineer (same as explorer 5.0).

#1. The thing troubling me the most is the wiring. My idea is to get a Wire harness from a mustang and hook that up to the Exp 5.0 and yes I know I have to put a distributor on it. Now do I replace the wiring under that dash with the wiring from the mustang or keep the stock harness and splice (I'm terrible at this because I don't know what any wires go where and what they are for)?

#2. Would It be easier to use a 88-93 mustang wire harness or use the same harness that came with the engine? (the exp/merc harness has a bunch of anti-theft crap & security crap I don't need) The wiring is greatly troubling me and I would greatly appreciate advise w/ pic from people that have put a EFI 5.0 in their truck.

#3. I plan to use a 4x4 manual trans from a ford 4.2l v6 so my question is, is it too big? If so what other trans could I use? Also if I got the manual trans and used the explorer wire harness I would have to make customization to the electrical part because the explorer is auto, and that is another reason why I want to use a stang wire harness.

#4. will I have to replace the differentials or will they hold up to a v8? I would be using the diff. from the 4.2l truck, but I'd rather keep stock to reduce build time.

If you decide to answer my questions I really need the answers for the wiring more than anything else. I'm good at fabricating and making adjustments and custom mounts, but when it comes to wiring, my guess is as good as your's.

This will be a daily driver to & from work and every once and a while messin' around but I want to keep the 4x4.

You could go carburered or....
Painless wiring makes a awesome stand alone harness for 5.0s (86-95) for around $500. It's a easy hookup. You would have to probably change some components on your newer 2000 truck motor to back date it to make it work.
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That's I'm planning on using for simplicity. No splicing or headaches! Worth the price.

You also want find a short accessory drive to keep clearance between radiator. Look at 94-95 mustang for the pulleys, brackets, and short water pump. Also, 90-91 Thirds are suppose to have short accessory drives too.

This is the best thread for Ford v8 swaps into B-series on this site.
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I believe you can swap the center diff from a 2nd gen or 3rd gen rx7 to beef it up.

If you want to keep 4x4 you are probably stuck with using the B2600 transmission, or find a transmission & transfer case from a Ford that will bolt up to your engine & also have the front driveshaft come out the correct side, then its custom driveshafts. The B2600, and pretty much every 4X4 transfer case is bolted to the end of the transmission.

As for the wiring, you will have to combine the 2 harnesses together. I would use an earlier harness and electronics, which may involve changing alot of sensors, since the newer computers with security and stuff built in will not work unless all the security components are transferred over (usually ignition key, dash, etc..). You will need to keep all the power and light wiring from the B2600, and all the wiring that goes from the engine to computer will have to be lengthened or shortened to fit your wiring routing. Wiring for gauges, power, ground, fuel pump, etc... will need to be spliced into the B2600 harness.

For my 5.0 swap I used a half mazda and half mustang harness. It worked but was confusing if you were ever looking for something. If I were to do it again I would use a 5.0 Painless wiring harness. Worth every cent of your investment and you have a detailed schematic of the wiring that is color coded and labeled.

Well I thought about it and I feel it would be easier for me to change the motor into carburetor. Wiring is too complicated at the moment and do not have time to mess with it. I need to get this swap done ASAP so I can start driving it. Yes I know the MPG will go down but hey, its a 5 liter, I'm going classic. Now all I have to worry about is the Transmission. I know where a T-5 is and can get it cheap. Does anyone know if there is a adapter for the T-5 so I can use the stock b2600 transfer case?

Thanks for referring to my project thread.

I agree, I would just go carb. Much easier for wiring purposes.

I think a C4 transmission fits just as well as T-5. But I don't have any idea how to get a transfer case to operate 4wd.
The B2600 rearend may hold up better than the B2200, but I am using an Rx7 diff. If I had to do it all over again, I'd swap it out for a Ford 9" for strength and better gear ratio options. I hate being at 3500 RPM at 70MPH.

I think you are making a huge mistake by not going FI. With the painless harness its basically plug and play. If you want reliability and no bs, FI is a must. Carbs are just a pain in ass.

My truck was originally carb'd so I didn't feel like finding an ECU from a FI truck and decided to stick with carb when I did the swap.
I won't say carb is a pain in the ass, because it's somewhat straight forward to troubleshoot and I haven't had any issues with my Holley carb. I wouldn't mind doing a FI setup with the painless harness though next time I do an engine swap project.

You see I love the idea but I'm strapped for money. I can get a Trans, Carb, & intake for under $500, (I know places & people) but I need to get this done fast & don't have time to wire stuff. But I will tell you this: I have a 351 Cleveland that I want convert to FI, and I will use that because I need a Mustang 5.0 ECU, and wire harness with a few sensors, so I will use the painless harness for that. And when I get around to it, I will be putting it in a lowered 91 B2600 Ext-cab that I want to revive, that will be my project truck.

This truck I'm putting a 302 in is just for getting from A to B, and maybe trail blazing in between (because it's 4x4). I payed $500 for it so its not in the best condition. & I need it put together asap.

So I need little more help. Does anyone know of a 4x4 manual transmission that will bolt up to a 5.0 but the transfer case come out the right side like the stock t-case? I was wanting to use the 4.2l v6 (which is a direct bolt up to the 5.0) tranny but the t-case comes out the left side, and I would have to cut a hole in floor on the drivers side and raise that part up to fit the t-case in. If I did this i would get the 9" front & rear diff. Any other suggestions?