Questions about Quest/Villager VG30E blocks

So the '93-'98 Quest/Villager came with a VG30E. I was digging around the interwebs to find out more about these engines to find out if they are basically the same w-series found on the 4/87+ Z31's. I came across some photos of a VG33, VG30 w-series, and Quest VG30 blocks. I'll post the photos/video below, but here is my question: Are the block castings different between the Z31 and Quest w-series? Look at the more reinforced valley between the cylinders on the Quest 3.0L block (deeper grooves). It almost looks like a VG33 block (extra bracing) but with the 3.0L bore and w-series coolant channels (see the small coolant port near cylinder wall).

Anyone able to chime in here?

First image (from NissanNut): top is VG33 and bottom is VG30 (appears to be w-series)


Second image: from eBay listing showing Quest VG30 short block (w-series coolant port)

Larger photo here: http://www.ebay.com/itm/1997-98-Ques…6bfff8&vxp=mtr

Finally, here is a YouTube video of a Quest 3.0L long block being tested - notice the deeper valley bracing
https://www.youtube.com/watch?v=VZG0BQS1RtE