Incommando

That is one of those "conventional wisdom" things that in many cases is not true at all. You can read constantly about something because the people posting te info just "know" their info to be true so they pass it on. Actual back to back dyno testing on various set-ups has proven that there is no single answer to the header vs. manifold debate. A recent study of a 360 AMC V8 in a FSJ using stock manifolds, "shorty headers," and full-length long tube headers showed solid increases in both HP & TQ with the long tube headers over the stock manifolds.The popular (and more expensive) "shorty" headers had little to no effect on HP or TQ. The greater the other mods ( carb/intake/cam) added to the engine the greater the increase in HP & TQ over the stock manifolds with the full headers. Like everything there is a balance. Some factory set-ups may be better than others to start with so there would be little difference after the header swap.

Well I am part of the way there as I have a '95 dual-diaphragm booster to swap on and my choice of 231 or 242 x-fers. The rear axle will be a 29-spline 8.25 I got from under a '98 XJ while the front is from the '95 the booster/m.c. came from. The '91 was a great buy at $200. I have driven it on round-trips of 400 or so miles without a hiccup. The body is rough although the cab floor is surprisingly in good shape. I am thinking of selling the KJ, which is actually a decent tow vehicle probably due to its 4000 # bulk, and picking up a new/newer DD. The MJ would become the occasional tow vehicle plus the inclement winter driver, another plus for the 242. Decisions decisions.... but either way the 2.8/ax5 '86 no longer seems to be an option.

Thanks for the link. I am going to bite the bullet and do the 4wd swap on the 91 as I already have all of the pieces. Well, I had all of the pieces but sold them or lost them and now I have them again.... :D I don't think the 3.4 will get me where I want to be namely a tow vehicle for the CJ. I will just have to live with the '91's rust or get the body done.

found some info out there that the '86 MJ does not have the same firewall as an '86 Xj and does not have the same swap issues. Does anyone have any info from someone who a=has actually attempted this swap?

I did the $45/month Walmart/Straight talk plan. Unlimited talk/text/web. It has worked well for me since October. The biggest downside is that you have to buy the phone upfront

^^^^ Nice

Much worse than a Renix to OBD 1 swap? The problem with the 3.4 is the AX5... :(

I am looking at an '86 LWB with the 2.8/AX5/207 drivetrain. Truck is decent but I am not in love with the drivetrain. I have a '91 4.0 MJ as a donor for the 4.0, wiring, any front sheet metal that needs changing, and the TCM for an AW4. As the '91 is 2wd I have a later 23spline AW4 and matching 231. Searching for swap gives me too much info ( around 10,000 returns) as the search function automatically ignores 2.8 and gives me everything with "swap" or "swapping" in it. I have read until my eyes are bleeding. If anyone has anything bookmarked or advice I would appreciate it.

yeah I know those track, they are the same they sold on ATV but I really like the way AD boivin are made, since you do not need to remove the tires from the truck I would like to see a side-by-side comparison test of the two. ;)

http://www.mattracks.com/contact/ :USAflag:

Wow. I wonder what it cost him to go from apples to apples on that axle swap? The difference between a 29 spline 8.25 and a D44 rear are moot. And with the same u-joints the HP30 & the LP hybrid LP 44 are a wash. But he did buy the bragging right of having RUBI AXLES!!!! :bowdown:

I was not talking about a JK D30/44 set. I was talking about a JK RUBICON D44/D44 set. The ones with factory lockers and deeper gears. Feel free to do your own Google search for the axle set that I was talking about and check the prices. My search was not local but brought in responses from ebay, pirate, etc... I noted the 5,500 as an extreme and said 3,500 was a common price. JK rims are hard to give away as many are ugly, they have limited appeal to anyone but JK or Grand Chero people due to the bolt pattern, and they came for the most part with very crappy tires. Goodyear SR-A's are horrid. Anyone swapping a JK D30 into an MJ is spending time,money, and effort with very little pay-off. Why pay to change the suspension mounts over choosing a butt-cheap bolt-in XJ D30? And then have a differing bolt pattern? What is the width of those HP44's you see for sale? The most common ones, Ford, are 69" or greater wms-wms depending on the app. How many people are getting stuck with the near-worthless (unless you use the Ford radius arms) 78-79 version with cast in radius arm wedges because they are buying a "hp44" without realizing they are not all the same? ( http://api.viglink.com/api/click?format ... 0293882881 )Although the HP design gets you a stronger ring & pinion set that is not a real weakness in the LP D44. They still have the smallish 297 u-joints used in many HP30 & most all LP D44's and the same ball-joints and those are the weak links in the D44, not the ring & pinion. The difference between LP & HP on the D30 is much greater as that IS a weak link on the D30. A D60 rear is not all that great of a step-up unless it is drilled for the larger 35 spline axles. Full-floater D60's are lucky to sell for $150 here due to that. To compete with a 14 bolt you need the D70HD ( not 70U or the other versions) or a D80. There is no comparison between a front D44, HP or LP, and a front D60 and the selling point for a D60 front is well within that $500-$800 range you list for the HP44's. Hmmm overkill and a margin of error or pushing something to the limits and keeping your fingers crossed for the same money?

Thanks for the info. I had not researched the JK 44 before and did not know the differences, which are obvious. I am pleasantly surprised because of the near-fraud Daimler pulled with the TJ's alleged D44 front. Don't know why they are bending so often. I wonder if the suspension stresses are just right to make them susceptible to bending?

I was assuming that you had adjustable control arms & trac bar with your 4" lift. If you do not you will need them to go higher. So even if you just bought front top spacers to make your front 4" lift springs equal the SOA rear on stock springs you would have to invest in the other suspensions pieces as well if they are not already in place. I went adjustable when I did my 4" lift. I was able to do the relocation trick to get my front brake lines right for a 4" lift but I don't think they have that much left for a taller lift if the front flexes much. Even with 32's I noted a power deficiency with the factory 3.54's. Depending on your tire size the stock gears may prove unlivable for you.

You can probably do this by saw-zalling the body ( most truggys are pretty cut up anyway) without any additional lift above the 4" you already have but you may need to limit up travel if it becomes an issue. If you SOA you need stock rear springs to give you 5" +/- of lift. If you have 4" lift springs instead you would be over 9" of lift. If you do the SOA rear with stock springs ( or the add a leaf/shackle combo removed if that is how your rear is lifted now) axles you can then add one of the many .75" to 2" ( as needed) front spacers available to the top of your current front lift springs to even it out on the cheap. Minor trimming on the body and the TJ flares got me this much room on an stock 2wd ( 1" lower than a 4wd) MJ. Those are 31x10.5's on it with no lift at all. There was a lot left to cut had I wanted to.

If the truck is lifted you may not need any driveshaft mods. If your donor is a '97 it should have the stronger 29 spline axle shafts

I would be curious about the axle stub shafts and unit bearing set-up. Although the D44 uses a larger ring/pinion, the TJ's versions at least were a low-pinion design that makes it closer in strength to a high-pinion D30 than many are willing to admit. I don't know about the JK but the way Chryco misled jeepers about the TJ front "dana 44" does not leave me hopeful. The fact that the JK D44 has serious bending issues and yet a true D44 was used under even heavier 3/4 ton trucks for decades without those issues makes me doubt the specs of the JK unit. If you have to sleeve and truss the axles, you can do the same to a HP D30. If your high pinion D30 has 297 u-joints, is trussed and sleeved, and maybe some super cheap C-gussets added, you are probably a lot closer to a TJ Rubi front at least with the same upgrades than folks think. I admit not knowing enough about the JK Rubi axles to make the comparison but, as listed above, I have my doubts. For someone else reading this later and looking for better than factory axles for their MJ, you might consider finding a relatively cheap Dodge D60 pass drop front (mine was $300) then get a $75 adapter from 4wheelsupply on Pirate to mate a Dana 300 t-case ($200 or so) to your factory tranny and to match the axle drop and have not only a superior front axle but a cast-iron-cased gear-to-gear transfer case that is light years stronger than the aluminum-cased chain-driven 231. Add $100 for what a 14B goes for around here, $125 for the shaved cover, and if you are willing to keep the rear drum brakes you are golden with just adding your lockers. A shaved 14 bolt has +/- 2" more ground clearance than a factory one, is stupid strong, and butt cheap to buy. Unless you get a smoking deal that is far far cheaper than the average price of a set of JK Rubi axles (and then add the money you are going to upgrade its shortcomings & replace any worn parts) going to 1-ton axles is cheaper. Checking 10 for sale ads, the cheapest JK Rubi set was $2,300 and that was with no brake stuff at all on the rear and everything from the ball joints out gone on the front. The highest set was $5,500 with $3,500 being a common price. And remember this is a front axle that guys are ditching because of its issues. You can get a true D44 bolt-in aftermarket axle with an air locker for about $2,800 ( http://www.4wheelparts.com/Drivetrain-a ... _pl=101965 ) or about $2600 with an electric locker & even cheaper ( $2300+) with a mechanical locker or a LSD front. Add a cheap but stronger than a D44 Ford 8.8 rear axle with discs and you are done without any fab time, effort, or expense for the front and minimal for the rear. Add that you would not need sleeves, adapters, or new rims to the savings and... :D On the front: Mine is 67 " WMS-WMS where a JK is 65" for WMS-WMS, so the width difference is not that great for anyone else considering that swap. A C&C 14 bolt is 63" so add some spacers to match up the track width front to rear ( or not..it isn't a huge deal) and call it a day. The brakes on my donor axles were perfectly servicable but I wanted to upgrade the rear and start fresh on the front. That is $650 of the roughly $1900 I have in my axle set with new lockers. The brake costs might be similar $$$ for the JK axle set if you wanted to start fresh with all new components. $1900 for locked one-ton axles that are as close to unbreakable in this app as possible vs. $3,500 for a set of axles that still need to be heavily upgraded & even then are several factors weaker.... Your choice.

Barnes is generally a little cheaper than RuffStuff and just as good IMHO. If you go to RuffStuff I *THINK* you can use the discount code PIRATE10 for a 10% discount. JK's are hefty little piglets. The lesser weight of the MJ may help those axles survive. I know the TJ front "44's" were hybrids but are the JK fronts pure 44 or a 30/44 hybrid like the TJ axle was? Although the locker is not selectable, I have less about $1000 in my 4.56 D60 front with all new pads/rotors/bearings/hoses/wheel studs/ujoints & a Spartan locker. I have no worries about it holding up under the CJ with 38's. I have less then that in my shaved 14bolt rear with new locker and disc brakes. Just for a price comparison with the JK axles you have a line on.

3 besides mine

Everyone is in love with horsepower and I am guilty of quoting it, too, but the real interest IMHO is in the torque number and the rpm range of the near-peak torque. I had a 12V CTD Dodge that was rated at 160 hp but 400 #'s of torque. Which number do you think was important? If you go back to the really crappy years, especially for American cars, of the early '80s and late 70's you will see that nothing had any horsepower. Heck a 454 Chevy from that era was lucky to produce 200 horsepower, less than the 3.7 V6 in my KJ, but probably had over 325#'s of TQ. A '79 or newer CJ7 304 V8 was a measly 125 horsepower! Matching the power band of your engine with your transmission ratios, axle ratios, and tire size to put the engine in its sweet spot for how you realistically use your vehicle is the answer to making most any engine work.

Thanks for that

When I drink beer it is usually an ale, be it Newcastle or Smithwicks or even Boddingtons. For a non-ale I drink Tecate. None of them rank up their with a good whiskey or rum. On the subject: years ago they pushed a lower alcohol beer called "3.2" for the lowered alcohol content in them. They were considered pisswater and generally only sold decently in states that allowed you to drink them at an earlier age than 6.0% and up beers. Flash forward 20 years, call the reduced alcohol beers "light" beers, and watch the people suck them down... Greatest alcohol marketing gimmick ever: make them buy 2 "light" beers instead of one full beer to get the same buzz...

I find many mixed reviews even today. A have personal knowledge of a red top that has been replaced 3 times in the last 18 months since it was purchased new and the selling dealer will not give a refund, exchange only, even though they acknowledge it is the batteries and their own tests could find nothing wrong with the XJ it is in. Even if Optima did fix the problems ( no way a certainty ) they are still the company that screwed a relatively small customer base over for years and years. Why support them?

Optimas used to be great so older versions are much better than the new ones. Then they got bought out by Johnson Controls (people looking to exploit the name), production was moved from the US to Mexico, the internals were cheapened greatly, and they still charge a premium price. Dozens of posts about this all over the net. Caveat Emptor for anyone still buying them.

What a beautiful place to fly a kite. Mine get eaten by trees