Amc Gearbox Ratios And Availability

I have started my next project, a heavy weight ajs (matchless)

have started to collect part's etc,have acquired a late amc gearbox

but it is a road box not a trials, any ideas out there what ratios do

i need and is there anybody specializing in making or supplying

internals for these gear boxes,any ideas also on rear shock and

spring rates (who's is best).for the heavy weights.

Colin