Having no luck finding a 4.0 replacement for my Disco, I've found a few 4.6's at a resonable price and miliage. One in particular is from a 2004 Disco. How where these motors, same headgasket and sleeve problem as the 4.0s? I know the 03's had a reputation for being hand granades in waiting. Is it worth finding 4.6 heads or can I reuse my 4.0 heads without a drop in flow? Anything else that may need to be tweeked, like BCM/alarm, trans/engine mount fittings etc.

Thanks!

 

Don't quote me on this but I think that the 4.0 and the 4.6 have the exact same block and heads, the only difference is the stroke of the 4.6. So I am sure you can use the 4.0 on the 4.6 and visa versa. The only thing you need to worry about is if it has secondary air injection or not.

 

Heads are the same, it should drop right in as long as the 2 motors are SAI or non SAI.

My Wife has an 04' and we dropped in a 4.0 with no issues.

You might want to put a 4.6 MAF and ECU to take full advantage of the performance, but it's not necessary.

 

ok, this might actually be financially feasible to save my Disco from being whored out to these rediculous craigslist offers haha

 

Some reason I thought the 4.6 used a little longer transmission housing.

 

If I am not mistaken the length is the same but the 4.6 got an updated transmission to hangle the extra power. I am sure someone else will chime in on this.

 

That is my understanding as well. The 4.0 and 4.6 are dimensionally identical on the outside. It's just the innards that are different (bore or stroke). I have also read somewhere about the transmissions being different.

 

Trans is different, but interchangeable. Some vendors sell a 99-02 and an 03/04 front drive shaft based on an inch difference in length of the trans.

But, if you notice the driveshaft that Lucky8 sells for D2s is compatible with 99-04'.

So, the length difference is neglible. Yes, 4.6 has a beefier trans, but a hp-22(99-02) trans will work in a 4.6 motor(which normally has an hp-24 trans).

 

I found 15 of them in NJ from 750 to 2k. I have a junkyard search engine.

 

just mixed rv8's, in general...... or 4.0's or 4.6's? not that the stroke can't be swapped, but just curious.