240Z/260Z/280Z have same diameter spring as 1200s. EDIT: 280ZX have much bigger spring perch.

King Springs for 260Z are the small-diameter type, same as the 1200. KDFS-04 is King Spring for 260Z (standard height). KDFL-04 is 260Z (Lo).

do Z's have same dimension perch as 120y

kings lowered 260Z front coils should do it for a street car.They're captive at full droop in a 120Y strut. 175lbs/in. I used them in my L series turbo 120Y - worked well on the street.

I have the B110 type, b210 same as 200B top (pic ref)

Which part of yours came out of a 120Y? Nearly all Datsun-Nissan tops use the same 123mm PCD mounting, but the two main types are 1200 (using high-pivot tops) and all others. See Strut Tops.

sorry I should of mention they came out of 120Y, wounder if 200B top fit, maybe there bigger in diameter for spring to sit??

Gemini springs are common use too

You can also raise the ride height by swapping the 1200 strut tops for 120Y strut tops. Raises it about 25 mm?

King Springs KDFS-04, about 40mm longer than stock, only slightly higher rate than stock. So it carries the extra weight of the CA18 at stock ride height, plus you get a smooth ride. You can also make the stock lower spring perch adjustable to fine-tune the ride height.

Hi guys have standard 1200 springs and they don't cut it to carry a CA18,
id like to keep standard ride high if I can,
what's your recommendation in size, strength & brands fulla's :)