Is the only difference between the W2 shafts and the stock version the location of the bolt hole or is there more to it than that?

On the oil pressure, another mate has a 408 w/- approx 540hp which runs about the same pressure at idle, but when hot goes down to ~40 psi. That one is still running in though, and still has the running in oil in it (ULX-110).

Took some photos last night but they didn't turn out very well.