Need valve springs for a N/A cosworth, lift will be 10.41mm on a Newman cam keeping the hydraulic lifters.

Standard cossie springs take a max lift of 8.9ish

Dont want double springs with titanium retainers, or need the spring seating milled out- cannot afford

Has anyone used kents VS30 (opel items) single springs and kept the original retainer.

Apparently these give the same poundage and can handle 11mm lift into the upper 7000rpms. Any info would be great