Hi Scottyb
I have used a standard 120Y speedo cable on mine. It bolts straight up without any mods. They are $5-$10 from the wreckers or $70 brand new from Nissan.

I have used a 3.75" Speco tacho in the standard clock binnacle. It fits in there almost perfectly. The tacho comes with or without an internal shift light and costs about $160 from any auto parts store. As an accidental bonus it matches the factory dash lights too so it doesn't look out of place. Kevin Rowley installed it for me by bolting it to the metal frame at the base of the dash and I ran a bead of silicone around it to keep it in place. Let me know if you want a product number or anything.
Sorry for rambling.
Regards Matty