[abrupt11]

Hello I looking to get info or ideas for a project.

I have a 90' YJ with the stock 4.2L (carb) and stock axles.
Spring over with 1.5" springs and TJ Flares to give that extra space.

I'm running 33's right but, have enough room to run 35's with flexing room.
If I run 35's my 4.2L does not have the high end power to push those meats and second afraid to brake an axle in the trails.

I'm thinking of swapping the engine out for a 4.3L vortec. From what I read I can still use the stock tranny and t-case right?
My question is will this engine give me the extra power I need?
How easy or difficult is this swap?
Do you all recommend a better engine to swap?

Now the biggest tires I'll run are 35's or 36's. And I don't need any crazy horse power to turn my jeep into a death machine.

Now the axles. I know mostly all axles I'll find that are bigger than the D30 & D35 are going to be wider. I wanted to keep the D30 in front for now until I find a swap locally and I don't want to look funny with a wider axle in back.
What would be my best axle options?
I here alot about the Ford 8.8 but, I can't find locally yet.
I have come across a ford 9" with drum brakes for $100.00 off a ford 55' pickup.
(58" between flanges, has steel tag w/2.75)

Any help or tips would be great!


Note: I have 4" Rubicon Express springs looking to swap for 2.5" springs.
I local to San Antonio, TX.

[abrupt11]

Check out this link for some great info.

http://www.novak-adapt.com/knowledge/chevy_small_block_v6.htm

I know this has be written about so many times but, I was just trying to get all the info I can.

Now that I have I'm ready for the swap!

[blakkbelt]

hey, i just got done throwing a 4.3 into my yj....pm me w/ any ?'s and i'll see if i can help out...good luck.

[JeeperDon]

I feel the 9" is too huge physically, so I'd hold out for the 8.8 (and I did). Yes, the 4.3 is great for 35's, assuming you gear accordingly.

[YJ_Aaron]

Don, why would you consider the 9" to huge? I mean they are roughly same size as a 44 not like the 60's and 14bolts that some of us have run.

Personally i like 9", They have so much aftermarket following parts are cheap and they make up to 40spline axles for them.

[Truth]

Why use a GM 4.3 when it's much easier to swap in a 4.0?? (Trust me when I say the 4.0 is MUCH more reliable) So you're going to go through all the trouble top swap in a motor with terrible elctronics and fuel delivery and leave your stock ranny and t-case? That doesn't make sense. You can put fuel injection on your present engine, swap the head with a 4.0, swap in an entire 4.0 (much easier than the chevy motor), or better yet...how bout a D300 instead? No need for a SYE, you can twin stick it, hell of alot stronger, or....what trans do you have? 999?? AX15?? Please don't tell me you have a puegeot (sp?) and are thinking of swapping a perfectly good engine.

Don't mean to be off topic but I've always been curious about this.

Don't think horsepower to turn a tire...think gears. I know a guy that uses 38" boggers in a sammi with a stock 1.3L motor. The 300:1 crawl ratio makes this thing unstoppable. With the fuel injection it runs upside down, or on it's side, and with the full hydro steer it can turn itself back onto it's wheels again.

I wouldn't recommend an 8.8, but if you can't find one local there must be no junk yards near you. We pull those things out of yards every week over here for $100 or less. Then clean them up and sell them. 9" from a '55 Ford? You don't want an axle from a vehicle that old. Chances are the housing is junk, and it will be difficult to get parts for. Think XJ D44, Chrysler 8 3/4, or even 8.8 if you have to.

You need to start looking for a local U-pull-it junkyard. Find whatever axle you decide on (yes, 8.8 is the easiest), and you can get easy fuel injection by robbing the head and electronics from an XJ. (wranglers are hard to find in boneyards)

Even better, swap in the whole 4.0 and AW4 combo. That would at least be some sort of improvement.

[JeeperDon]

Originally Posted by YJ_Aaron

Don, why would you consider the 9" to huge?

I don't know, just preference maybe, but the 9" seems like it has less ground (rock) clearance than an 8.8 for not much more strength (9" v 8.8"), strength that is also likely not needed for a 6 cyl motor. I will give you that the 9" has a nice smooth bottom. I have been meaning to take the grinder to my 8.8 and smooth out some of those sharp casting edges on the bottom.

[ErikJordan]

Originally Posted by JeeperDon

I don't know, just preference maybe, but the 9" seems like it has less ground (rock) clearance than an 8.8 for not much more strength (9" v 8.8"), strength that is also likely not needed for a 6 cyl motor. I will give you that the 9" has a nice smooth bottom. I have been meaning to take the grinder to my 8.8 and smooth out some of those sharp casting edges on the bottom.

smoothing an 8.8 =

[abrupt11]

I have the gearing (4.56's) to make my tires turn with no problem. It's just that 4.2L doesn't give me justice on the highway. It's like no high end plus my engine is at 138,000 miles. I know I can take to 200,000 but I have had bad problems with the engine and carb (never ending). Plus gas guzzlerrrrrrrrrrrrr

I have the AX-15 Trans.

I know this problem is common but, my throw-out bearing goes out all the time and it's a pain to replace.

I just offered a guy $1000.00 for a wrecked 2001 Chevy s-10 blazer with the 4.3L (44,000 miles) and 4L60E auto trans.
I was thinking of converting to an automatic to get rid of the throw-out bearing and be in comfort.

This isn't my daily driver but, I drive it alot.

I thought about swaping to 4.OL since it's pretty much an easy drop in but, I just don't like the throw-out bearing design in the manual trans jeep.

I haven't really looked as far as the axle. I know I can get my hands on one if I really looked around.

What does the Chrysler 8 3/4 come in?

[Truth]

Originally Posted by abrupt11

I have the gearing (4.56's) to make my tires turn with no problem. It's just that 4.2L doesn't give me justice on the highway. It's like no high end plus my engine is at 138,000 miles. I know I can take to 200,000 but I have had bad problems with the engine and carb (never ending). Plus gas guzzlerrrrrrrrrrrrr

The 4.3 will use just as much, if not more fuel than the 4.2. If your carb is dialed in properly you shouldn't have any problems. (They are unreliable though, I know) My 4.0 has 250,000 miles on it, and it stills runs strong. Driving it all the way from Chicago to Colorado to wheel, (and back) this summer.

I just offered a guy $1000.00 for a wrecked 2001 Chevy s-10 blazer with the 4.3L (44,000 miles) and 4L60E auto trans.
I was thinking of converting to an automatic to get rid of the throw-out bearing and be in comfort.

You'd be better of to find an XJ deal like that. It would be more reliable, and easier to swap. They are out there, just look around.

I thought about swaping to 4.OL since it's pretty much an easy drop in but, I just don't like the throw-out bearing design in the manual trans jeep.

The AW4 is a strong auto trans.

What does the Chrysler 8 3/4 come in?

Old mopar muscle cars. I had another thread about this axle in here somewhere.

[abrupt11]

Is the AW4 spline count the same as the np231 ( I think it's 31)?

All I really want is to be able to throw on 35's and hit about 75-80 mph on the highway not flooring it. Right now I'm hitting 60-75 mph tops depending on wind and incline flooring it. I love the low end on the 258 though.

[Truth]

Originally Posted by abrupt11

Is the AW4 spline count the same as the np231 ( I think it's 31)?

Well, it does have an NP231 bolted to the back of it.

All I really want is to be able to throw on 35's and hit about 75-80 mph on the highway not flooring it. Right now I'm hitting 60-75 mph tops depending on wind and incline flooring it. I love the low end on the 258 though.

In that case you need better gearing.

[abrupt11]

If I go any higher on my gearing my RPM's will be super high.

I'm running 2600 to 2800 RPM that's high to me. I'm just making my engine work harder and I'm afraid to see a rod shoot pass my hood if I run it any higher.

I'm swithing to 35's soon so I know my RPM's will come down a little.

[JeeperDon]

The AX15/231 has 23 splines. Both other YJ trans/231 have 21 spline. My 4.3 ('02 w/18k mi) gets me a whopping 13 MPG, but with the sound from the Borla exhaust left over from my 4 cyl, and the power compared to the 4 cyl, I could care less.

[abrupt11]

Originally Posted by JeeperDon

The AX15/231 has 23 splines. Both other YJ trans/231 have 21 spline. My 4.3 ('02 w/18k mi) gets me a whopping 13 MPG, but with the sound from the Borla exhaust left over from my 4 cyl, and the power compared to the 4 cyl, I could care less.

13 MPG is pretty good to me. I'm doing like 10 MPG.