A standard 253 driven hard will smash an Aussie box so no hope if you drive a 308 like its meant to be I've got a couple of m21 boxes stashed away if I can get an original girl but will have to baby it or get a turbo block and put a 400 or 700 behind it . I bet a few Aussie 4 speeds were smashed in the old van pull tug a war days