Why do you have TR6 plugs on there?
You're not bumping compression or adding boost.
If you want to make more power, 10:1 pistons, IS3 NA cam and a very nice set of heads would be a good start. Port match the LIM, they're known to be of **** quality casting.
Fabricate some long tube headers.
But at the end of the day, 250 WHP will require spinning the crap out of the engine, which the rods don't like, and a huge cam which will suck. Consider finding a Holden intake manifold. Or F body and porting the crap out of it.
Also perhaps a little stall to help with the cam being a whore. ZZP Al heads would be ideal, but they're unobtanium now.
