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Buford 02-24-2013 08:49 PM

90 yj 2.5 to 302 Need Help
I purchased a 1990 yj with a 2.5 and 5 speed, with only 94,000 miles. I like the jeep but it wont get out of its own way. I could live with that, but now it is loosing a quart of oil a week from blow by. It is still running OK. Now yes I dreamed of a v8 swap when I purchased it but not a month after I got it.

Being a Ford guy I plan to install a 302 Roller motor, but I know the trans will not handle it. AX-15 is an option but they aren't much better. So I am planning on installing a m5r2.

So here is were I need help.
  1. Will the np-231 attach to the ford trans??
  2. If not what ford trans will fit in the YJ??
Any help is appreciated

Blacksurt 02-24-2013 10:36 PM and advanceadapter would be a good place to start....

Buford 02-25-2013 08:11 AM

Thanks, I understand that there area adapters out there. I am looking for what bolts together it simplify the build and spend less.

Presleighsdaddy 03-01-2013 10:41 AM


Originally Posted by Buford (Post 3416872)
Thanks, I understand that there area adapters out there. I am looking for what bolts together it simplify the build and spend less.

I have a 90 2.5. Do u still have the fan shroud. If so would you like to depart with it.

Buford 03-02-2013 02:09 PM


Originally Posted by Presleighsdaddy (Post 3437736)

I have a 90 2.5. Do u still have the fan shroud. If so would you like to depart with it.

Not yet. I have a little time before I switch engines.

kywaterman 03-02-2013 11:09 PM

As said earlier Novak is a great place to go to simply read, they have tons of info easy to access on motor swaps. It gives lots of detailed and accurrate advice on all subjects of the swap.

sp33dfr33k 03-05-2013 01:16 PM

A guy to look up on the forum would be "Ibuildembig", I believe he's contemplated a Ford swap and he's full of knowledge... Another thing to look at would be the options that were factory in the Bronco, and V-8 Explorer. Even if they don't exactly fit, they'll give you a starting point to go by for knowledge of application and parts used...
Ford Explorer - Wikipedia, the free encyclopedia
Ford Bronco - Wikipedia, the free encyclopedia

Borg Warner 5-Speed Transmission Identification |
This will help you in identifying which trans you'd like to use, from here look up which 4x4's had it as an option.

Just remember Wikipedia is not always 100% reliable, it takes a lot of research from that point until you find someone that's done it already.
Hope it helps... The are many options available, but we don't know your mechanical aptitude, or abilities, or background.

Good luck with the build, I happen to be a fan of the Mustang, I've owned 5 in total, but built 3 from bare bodies, a '68, a '74, and an '84. Of those three the '68 was the only one that had a V-8 originally (289) but the '74 and '84 were swapped TO V-8; from a 6 cyl in the '74, and a 4cyl in the '84 (convertible). The other two that I owned were later model, factory V-8 cars that never needed anything more than minor perf. mods. My Bronco was originally a 6 cyl. It left my possession, as the same 6 cylinder. I was re-introduced to the Wrangler while the bronco was dying, and decided to invest in a jeep for it's sheer ability to do literally ANYTHING, it's cool factor, as well as their infinite following, and aftermarket parts availability. I'm doing my first all-out 4x4 build now. It's a '79 CJ / '95 YJ / '75 Cherokee Chief (360 drive-train).
Well, good luck... See ya' in the forums...:punk:

OverkillYJ 03-06-2013 04:06 PM

I am going to be doing this. I am still not sure what the best combo TC/Trans is. The total length of the drivetrain needs to be heavily taken into consideration. Especially for me with an SOA and extra lift on top of it. My driveshaft angle is steep and the Driveshaft itself is pretty short. The only way my rear driveshaft will handle the power with the type of wheeling I do is without a CV shaft. Just need a strait 1350 shaft. The NP231 will handle it without any problems, and the AX15 CAN handle a V8, but it is not ideal. Also I believe there are shorter transmissions that bolt right to a 302, but then mating those to the NP231 is the other part. I am interested to see what you find out here.

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