an NA V8 maybe.. not an NA 6
best i've seen is a mate of mine with an NA 300zx who has 155rwkw with a hell of a lot of mods...
as said above, i've got an rb20det for my 170rwkw with FMIC, 3" exhaust, 14psi, rb25 turbo, cams+gears (as far as engine mods go anyway)