good on you for sticking with the Holden V8
LS engines in early Commodores are getting boring. I tend to skip any early Commodore thread when there is an LS engine in the equation.
Whilst you may be a little misguided in your understanding of the Holden engine vs LS, you can get a Holden keeping up with a stock LS1 for very little money. But beyond that, yeah as Ari said it's going to cost a fair bit extra - mainly due to the fact that aftermarket performance parts are low volume, generally limited to only a few Australian manufacturers, so costs are very high compared to any US V8.
My 5L is by no means a big budget engine, only a mild cam, flat tops, even the heads are stock. Most of the money is in the intake manifold. It's good for around 275rwhp - not overly impressive by LS standards. But the funny thing is, I've got video of my humble 5L powered VH sitting up the bum of a 6L VE for several sprint laps around Qld Raceway. Despite this VE making (on the same dyno mine was measured on) roughly 80rwhp more than my 5L, it just couldn't pull away. I realise the VE is a heavier car, but it's a lot slipperier car than my boxy VH, according to the dyno it has an additional 80rwhp and it had a lower diff ratio..... Admittedly at the very end of the straight it just started to get its legs (around 190kph), but it just goes to show that top end additional hp isn't overly useable unless you are going to gear the car low enough to keep the engine in it's sweet spot. And the VE driver wasn't exactly short shifting....
Holdens have small port heads, which work well at low to mid range but the trade off tends to be top end. The LS engines have the larger port heads which tend to yield good results at higher rpm, but at low-mid range they suffer.
