Our valve springs are custom made to be 50% stiffer than stock. They are not just springs from another engine and are a direct fit. No modifications need to be done for them to fit. They are to be used with your stock spring seat washer and spring cap retainer. Simply remove your original springs and install these in their place.
https://www.benzinjection.com/....product-page/perform

These valve springs are much stiffer than stock and are a direct fit. No modifications need to be done for them to fit.
https://www.benzinjection.com/....product-page/copy-of