We're only running a stock 308 bottom end with yella terra heads, small hydraulic cam, edelbrock performer manifold and a 600 vac sec carb (along with trimatic with 2500 stall and locked 4.11 diff). That combo pulled 146rwkw, but yet to see it's full potential as me little bro who races it is still learning to control the car.
Kev was running a stock (as far as I know) V6 with 4.11 locked diff and he whooped ass in B grade. Not sure on the exact specs but a VL there is making around the 170rwkw mark, it's a 308, solid cam, carby heads, and that thing is right up there in A grade.
Ya don't need much power in dirt circuit to get good results, IMO the suspension is where most of it is at (it helps if ya can drive too lol).
I've seen a few injected 5L's out there, but the majority of them are stock. Maybe check out the website (
www.dirtcircuitsa.com) and have a read up on a few cars....not many buildups are on there but might give ya some idea.
We're changing to VN heads hopefully at the end of the season. For a budget 308 build, stock VN heads are the way to go. Decent gain for little cash!
There's also a few gen's out there now too, which do a wicked job. And a few jap motors are popping up, and more people are playing with AWD....it's progressing!