has anyone changed the engines in there x to say from the v6 to a v8 that i have laying around i know there would be some body work but would you say that be a good mod to do for the powere the x needs it would have 380 hp

Nobody has done an engine swap on an Xterra yet. Well, except Carlton who had his original one crap out at something over 100K and he put in another used one. The only non-VG33 engine swap I know of that ever got past the dream stage was an LT1 that a guy was going to put into his Xterra but I don't know that it ever happened.
I forget who he was, but he had a lot of aftermarket companies behind him at one time, including a company that built an interior roll cage for his X, and he was associated with the 4x4 Evo off-road computer game. He kinda got run out of here for a few reasons. I know he had the V8 and quite a few other big items procured for a complete overhaul of his X, but I don't know that it ever actually happened.

As for doing it, anything is possible if you throw enough money at it, but until I see it done, it's just an idle fantasy that a few crazy people have.

Brent

so your saying i would need sponsers or just alot of cash ok but i wish nissan would drop the 4 banger and give 6 and 8 that be cool

Have you seen the 2005 ?
250+HP 4.0 V6.

I could have been seeing things but i thought i read about the GOX sponsered rig having the 3.5 from a pathfinder.

I could be wrong, but i thought i saw it in a very old magazine.

it wasn't gox sponsored.

it was nissan, clamini, eaton and a couple other companies... it was called projectX and it did have the pathy motor

And transmission, and t-case as I recall. The whole shebang had to be swapped, can't mate a VQ35 to a VG33's tranny...

I found this on a poorly designed web site http://www.geocities.com/eeyore_not_tigger/Nissanrwdswappage.html
but here is an excerpt. Perhaps a head swap from a different model VG33 with DOHC would add some serious hp?

Like the KA24DE,the VG is one of Nissan's common workhorse engines.It has seen use in the Maxima, 300ZX,200SX,Frontier,Hardbody pickup,X Terra ,Pathfinder,Stanza,Quest and the Mercury Villager.The engine is available in either 3 liter(VG30E) or 3.3 liter (VG33E) dispalcement.It has single overhead cams and depending on application and year will either have a timing chain or belt.It is of an Iron block and aluminum head construction.As with any manufacturer, the front drive and rear drive engines will not interchange, although individual components might.This engine has been around since the mid eighties,so they should be easy to find in junkyards.I believe that the horsepower ranges from a low of 160,to a high of around 215(not really sure)in the supercharged 3.3 liter available in the X terra and Frontier( which would be a neat swap into a mid eighties 200 SX originally equipped with a VG30E!)
Used in only three applications that I know of,the Maxima SE(VG30DE-190 hp),300ZX(VG30DE) and 300ZX Twin Turbo(VG30DETT-300 hp).These engines ,like all Nissan engines,are extremely well built. The twin turbo even had oil squirters to cool the pistons!The engine has dual overhead cams,a main cap girdle(I piece main cap),high nickel block,forged crank,and forged rods.(I'd really like to see one of these or a RB26 swapped into a 69 Camaro just to mess with some people who hate either domestic or foreign cars,wouldn't that be fun?)
Nissan's newest V6,it's installed in Maximas,Altimas,350ZX's,and the Infiniti G35(JDM Skyline) and I35. Horsepower varies and it has 255 hp in the Maxima and 285 in the 350ZX.It's a 4 cam engine that's all aluminum in construction and displaces 3.5 liters.Other than that,I don't really know anything about it.

I think he ended up parting out much of the truck on ebay. Yellow X with the yellow roll cage? cre8tor I think was his name?

Yup, he did put a lot on Ebay.