I’m throwing around the idea of doing one myself, so I thought I’d pitch it out there. Essentially that Vortec (also known as the LM7/LM4) is of a similar design to that of the LS1/LS6 thats used in the Z28/Corvette, and I’ve started reading about people doing them for budget builds, since they’re cheaper than an LS1 and can get about the same power. The intake on 5.3 needs to be swapped for an F-body one since they don’t sit as high. I found a thread of a guy doing something similar, so it might be worth a read: http://www.ls1tech.com/forums/showthread.php?t=825294&highlight=5.3l+240sx