Yeah holdens always been more about a 'real' power figure which doesn't equate to much 'rwkw' compared to ford who list their number as almost 'rwkw' number. Not hating on Holdens, I actually like both. Holden have better interior and features, and update the nicer things more often, ford have better gearbox / engines IMO
There's 2 ways to go about an SS, big dirty cam and exhaust, keep it N/A for just over 300rwkw (ish)? or just bite the bullet and slap a charger on it from the get go for 400rwkw (ish)