Hey Sambo
when you're done maybe you can rustle up a few Vics and we can head over to Lake Gairdner (SA) and clear the pipes
http://www.dlra.org.au/
(dry lake racers Australia - I think Deb/Doug were considering going to speedweek this year until cancelled)
Just on the whole rear ratio thing - If I had a T-56 and overdrive then I'd be going for pretty high(numerically) diff ratios, you'll have more punch in the lower gears when you need it and still have the ability to cruise up the Hume to Winton
LoBelly