Thanks for that Shaun however,

How do you get your speedo working if not using the Silvia speedo ? and I agree I don't need the whole silvia dash but maybe as Shoota suggested the gauges into my existing '81 round dash setup might work.

Shoota, I got them separately so I don't have the loom in the middle
From what I can research I have the 'Auto Harness' the 'E.F.I. Harness' and the 'Engine Room harness No.2' as well as the shifter with its plugs.

It looks like I need at least some of the number 1 'Engine Room Harness' and some of the 'Main Harness' (at least the plugs for the AT computer and maybe the combination gauges).

I DO have all the Looms from an EXA - that will be my next avenue - chop chop