What im thinking of doing is a new school/old school build... what i want to do is put all cherokee drive line (motor, tranny, transfer case, front and rear ends) under the CJ7 i have. So it will be able to climb steep hills and start good in the cold. Keep it all leaf springs. I think that it would be cool and different. Any ideas? Or even better Pics of this already being done?
That would depend on if it were automatic transmission or manual transmission.
FSJ MANUAL transmissions are set back about 5" so the shifter is better located for the driver to use,
But that same 5" in a CJ Jeep will put the shifter too far back in the vehicle and look pretty silly with the stick between the seats!
It also takes 5" of drive line space you need for the rear drive shaft.
If it's an Automatic, you might just get away with it depending on the transfer case,
Some are quite long in the FSJs and will eat into your rear dive shaft length.
Wider FSJ axles will give you better stability on the trails, but if you keep leaf springs you will have to outboard your front spring mounts at the frame.
This is usually nothing more than bolting on some supported angle iron mounts for the springs to mount outboard of the frame, and is VERY doable,
Many of us have done this in the past in one day, so it's not real difficult,
But you WILL have to research the subject of 'Out Boarding' and make up your own mind.
Newer vehicles have Dana 35 rear differentials in the rear, and they aren't worth transferring.
You would be better off with something that was a little better designed and stronger.
Older Cherokees have strong axles, but don't have fuel efficient drive trains.
The ability to climb 'Steep Hills' usually has as much to do with wheel base (how much distance between axles) than anything.
Short wheel base vehicles have a tendency NOT to get good traction for steep climbs...
The tires are too close together, and if one gets into something 'Slippery', all the tires are into it.
Longer, wider wheel bases/track width do better because they don't tip as easily, flip as easily, and get traction in different locations so you don't loose traction as easily.
Keep your vehicle as low to the ground over the axles as possible.
Your axles determine your ground clearance, so large tires will help,
But a bunch of weight flopping around on tall springs over the axles doesn't help you one bit,
And the higher up you put the vehicle body on springs,
The higher your center of gravity, and there WILL BE a direct reduction in what you vehicle will do the higher up you put it over the axles...
Personally, I'd look for a reasonable fuel injected engine, light weight, durable,
Probably a fuel injected V-6 for under the hood.
Since you don't go up really steep hills fast, huge amounts of horse power aren't needed,
And factory fuel injection will keep you satisfied when you are climbing.
I would look for a transmission and transfer with as much gear reduction as you can wring out of them...
Crawl reduction will get you up hills and over obstacles without having mega-horsepower which is VERY expensive.
I would look into axles that have good strength combined with good ground clearance...
Straight hill climbing won't take porthole axles to do,
So be on the look out for a D-44 or Ford 9" in the rear,
And a D-44 for the front.
(Rock climbing is another matter! Start looking for Dana 60 or Corporate 14 bolt axles!)
A factory Dana 300 with 4:1 kit would be pretty good behind a transmission with a deep 1st gear,
But you would probably be better off with a good used Atlas II transfer case, depending on how steep we are talking here...
And by the time you have the Dana 300 rebuilt with a 4:1 kit, you can buy an Atlas II used...
Now, if you are talking just having fun in the Jeep,
Slap that FSJ drive train in there and go wheeling!
I've started with FSJ drive trains many times...
As the body got knocked off, we replaced with mostly tube frame, and they work GREAT for just plain wheeling around looking for places to get stuck!
I've also yanked the drive trains out of FSJs and plugged them into CJs,
It's fine to do that, but a LOT of work to get things 'Just Right',
And it's no more fun that pulling the body off an FSJ, welding up some ugly as sin tubing frame around the driver, and pounding the crap out of it!