There are no cylinder head modifications required to fit these springs to your head.

This is a brand new set of 16 double valve springs that will fit all Ford Cosworth YB 16 valve cylinder heads. These are the same components we would fit should you require them fitting in our workshop and we usually use them with BD14, 15 and 16 cams.

There are 32 springs in this package. 16x large outers and 16x small inners.
The original spring retainers and collets are re-used with these.