1. If you are monied, try a CRS or Dellow bell housing and Toyota Supra 5-speed gearbox. The drive shaft needs to be modified to fit the Toyota yoke. The box is used in Commodore Challenge racing, and cops 290 hp+ in a 1350 kg 253 V8...without breaking!
2. Second option, an economical one , is just the single rail BW 4-speed. As long as it hasn't been thrashed and the nylon ball holdin the shifter is okay, then it's a drop in with the right bits. The Cortina ones don't fit unless you want a bench front seat...the shifter is much further forward (127 mm). The XB/C/D/E/F cars had them, and the best one is the EFI XE one which has closer lower ratios which would suit a 3.23:1 set of diff gears. The stock XF ute had a 3.47:1 first , 2.00:1 2nd, and 3rd was 1.43:1 which is way low. The XF got wider ratios, because customers complianed of over gearing! The XE EFI had a 3.06:1 first, 1.93:1 2nd, 1.31:1, 3rd. Same as 302 V8's. An XB-XE 351 has around 2.42:1, 1.78:1, 1.26:1 on its single rail.
3. The nicest one, if you can get it, is the T5 5-speed. It isn't very nice price-wise, but is fairly strong (not us good as a Single Rail, though), and has a nice lopeing overdriven 5th. It does have wide ratios , though.
4. TopLoader 4-speed. Can be a goodie, but mainshafts are no longer serviced in Aussie off the shelf, and the linkage is obstructive and the tranny tunnel needs a few smacks to clear the linkage. It's bullet proof, though! Nothing to put 450 hp through one of these. All you need is a toploader bell housing off a pre XB Falcon or early TC Cortina 6.
9999. Make sure you don't get a 3.3 5-speed gearbox. The XE version has perfect ratios, but the thing was designed for Sigmas and Commodore 4's, and was so overtaxed in a 3.3 1320 kg Falcon that a 4.1 will keel it dead!
, a cost of $700-900 is typical (new kit price $1700 or so complete). Fords may be cheaper, but not sure. 