I have vg30 in my 620. The vg30 was from an 84 300zx.
I removed everything that i didn't need to make the engine run.
With the wiring I purchased a new fuse box with 12 fuses and wired it up. I din't use the 300zx fuse box as it had thousands of fuses and relays for things that i wan't going to use
Get yourself a wiring diagrame for the pathfinders engine loom and study it.
If the engine came complete with the harnes atached your in luck.
I removed the EGR, injector fan, idle up solinoids, cruise control and some other things. The 620 runs good and i have done 3 14 hour trips over 3000km's with no issue within the last month.
I did use the alternator from the vg30 and wired it back to the 620's harnes removing the voltage regulator.
i hope this helps :geek: