IB5 out of a mk5/6 escort.
Ka 1.3 gearset
Use the FD out of the IB5 and fit the LSD from your standard box. This will give you slightly taller gears which I prefer, more sensible rpm at 70mph.

(If you want identical ratios you'll need to source a PUMA 1.7 FD and the lsd will need modifying.)

This is a direct swap, bigger bearings as standard, more webbing on the box making it stronger, and its not like most BC boxes which are 20+ years old and suffering from metal fatigue.