I put a Tremec t56 Magnum box in my LX SLR Torana behind a Holden V8 (304 injected) I used a Dellows bell housing. These boxes are simular to the tr6060 box in the VF commodore, but have a different extension housing and have both mechanical and electronic speedo inputs. So you can still use your speedo cable set up. I used the concentric thrust bearing same as commodore and made my own under dash hydraulic master cylinder.( simular to Mall Woods}

Clutch is very light and excellent feel. I didn't cut my tunnel and the box fits reasonably well, but if your after the perfect drive shaft angle you might need to do a slight mod to the tunnel (wouldn't need much). The Magnum box comes with different gear shift/stick points by bolting the shifter in three different positions. I just reversed the top shift housing (four bolts) which lined up perfectly for the original Torana console. I got my box off Summit racing and they shipped it to my door for $3,800 plus freight. This was around six years ago but I don't think they have gone up much since, and there are plenty of companies in Australia selling them now. At the time they were only new on the market and Mall Wood was the only one selling them locally. also Mall wanted $8,900 back then. These boxes are rated at 700hp and different overdrives are available. Mine is a .65 6th gear overdrive.

I also have a Tremec TKO 5 speed in the hatch, although its a nice box the T56 is better again and fits better in the tunnel. The TKO shift fells a bit like a truck and agricultural compared to the Magnum box. The Magnum box just seams to have a perfect close ratio for every driving situation.

Hope this helps.