Some people like dogs.
me being one of them.
torque, at 9000rpm.....for starters you'll be hard pressed to make an L24 rev to 9000rpm, much less an L28, i dont care how much $$$ you have. be reasonable 7500-8000 max
1st things 1st, go pull the head off and go get it ported....a lot. You want the ports to curve in a nice arc from the valve seat as high as you can get them before dropping slighty at the edge of the port. this alone is the key to big power from an L series 6
flat top pistons, total seal gapless rings, RR4 valve springs from Performance Springs, and a 586741(part number) cam from Crow Cams.
get the bottom end sorted by gettting it all balanced and shot peened. you will want a high volume sump and hi pressure oil pump. i seem to recall the 280zx having the best "standard" oil pump. these can be modded to produce more flow.
last of all go and buy an inlet manifold to run triple 45mm webers. (this manifold can also be used if you wish to upgrade to EFI later.)
and three weber carbs. 45mm are the biggest you could run, 40mm will do it but will probably be the weak link.