One interesting thing I did find out from the YouTube comments, besides don't read YouTube comments, is that the engine is a RB26 head, RD28 block, and 3.2 liter stroker kit. About six years ago I bought an RD28. I thought it was interesting. Diesel engines are almost always the strongest of the line. The oil drain was in the center of the block, and I had a couple of RB30's so I never really got that far into it. Might have to have another look at that lump, or just ignore it for another six years. Probably the later.
Godzilla Motorsports posted a picture on Facebook of a VR38DETT that they just got in. More displacement = more power. They should be able to make even better power, and go even quicker with the V-6 vs the inline 6.
Watch the 6.63 @ 211mph video and a short dyno video after the break.