internally is everything interchangeable without mods like the crank, rods, pistons?

are the pistons exactly the same? could I pop in 4.0L pistons into a 3.9L? 4.6L pistons into a 3.9? OR do you just use the rods...

I picked up a 3.9L motor since in the future it can actually be worked on, like it can be bored and oversized pistons used later, whereas the unlucky 4L and 4.6L has no source for OD pistons anywhere in USA.

so while I have the motor out of the truck I was wondering if you guys ave any recommendations for upgrades b4 I drop it in my off roader land rover.
I already have the hot cam and intake and carbs, think I'll use my 4L heads

do you guys think I should put in a bigger crank & rods while its on the ground?

Anything preventative I should do while its out?

sorry for all the questions, I'm not a mechanic but I can turn a wrench.

thanks in advance

 

forgot to ask, is the 95 transmission the same as the 98? How about the transfer cases?

 

You will find that most people don't know anything about the motors on the inside.
I'm one of them.
I have gone to RPi in the UK to get the info I needed.
They have parts for the V8's and have a stroker kit that has a list of what it takes to
make one.
The 3.9 and the 4.0 are the same they just forgot to round up not down.
3950cc = 3.9 1995 and older and 3950cc = 4.0 1996 and up.

If you are going to have more displacement you may have to have the ECM reworked to read the changes done to the motor, RPI can tell you this.

Good Luck.

 

If your going to put a 4BBL on it you dont need to worry about the ECU.

A DI is a DI, from '89 when it first came out to '99 when it was shelved.
SO your trans are the same, the t-cases are the same, hell, the t-case from a 2002 will fit in a '96 and vise versa.
The diffs from ALL years are the same, the engines are the same block and heads, the t-cases are the same, the only time things changed was in 2003, the transmission that mates to the 4.6 is longer, it has a bigger pump to handle the extra torque.
You can bolt a 4.6 to a 2000 tranny but it wont last 200k hooked to that engine.

 

Many of the internal parts are not interchangable, the trannys are not the same and there are some small differences in the t/case.
As far as boring out the cylinders, that is what caused Rover the most problems, the 4.0 is tapped as far as it can/should go.
What exactly are you wanting to do with your engine?
If you are thinking about dropping a 4 barrell on it, you will have ECU issues.

 

thanks for the info guys, it really helps a lot.

I picked up a 95 disco for the motor (all other parts on it are for sale now), and upon removing the torque converter I was worried if the 95 motor and torque converter can be put in the 98, because the 98 torque converter & plates wont mount to the 95 motor (3.9). I'm hoping the depth is the same, will measure it tomorrow to make sure it can fit in the 98's tranny. the cranks are not the same bolt patter on the back side

I'm not sure about carbs and the ECU, my 98 don't have an ECU anymore. fuel injection is cool, but only if u know what ur doing. and so I don't deal with that stuff. I don't have to smog check here in my state, so no worries.

Right now all i want is my 98 to run so I can sell my 01. except for the motor and a roof rack and front bumper/winch and stereo, my 98 has everything i want, so gonna sell the 01. So I need to put that high mileage 95 motor in it for now (sucks) but it's my only choice, spent all the money I had on the purchase of the 98.

I thought I could do some minor rebuilds to the 95 motor b4 i put it in, but now I think why waste the $ and just save up for another motor or parts truck down the road. guess i won't be 4 wheelin anywhere for a while, except to the beach or fishing