Diff Ratios

[Deuce]

Hi I have a 2008 VE SS manual. It’s making 484hp at rear wheels, and is essentially a second car/toy. My question is I’ve blown the diff and I’m upgrading to a Trutrac, however I don’t know which ratio to choose a 3.9, or a 4.11 which would be more suitable? Given the fact that the car has a massive cam, sits on Nolethine engine and gearbox mounts, and breaths through pretty much 3 inch straight exhaust with no cats, I’m not looking for fuel economy, just performance.

I'm not sure if this helps. But is something to think about (similar to pollushon comments)
15years ago I had a series 2a Land Rover, short wheelbase with a Holden 202 conversion and driving around it was normal only to use 2nd 3rd and 4th. The motor was alot torque-er than the standard motor and 1st was pointless unless starting at the lights on an incline.
Ripped out the diff heads and fitted 3.9's. Stock is 4.9 and the previous owner had already swapped to 4.3 R/rover diffs.
1st gear was more usable now, and top speed was improved also (approx 78mph from memory).
Moral - don't gear it to the point that 1st is pointless. Maybe do some online calculations to see what 1st gear range is with different diff ratios.

If your power is from a turbo charger addition, then stock gearing helps the turbo spool in early gears. Although I feel this is N/A power?

 

[vr304]

3.9’s are the sweet spot I reckon, as someone else said 4.11’s will make 1st gear pretty much useless