Single Valve Springs - Heavy Duty Street - M30 (early)

Performance part. Heavy Duty single valve springs for the M30 engine. These springs will work well with the any upgraded camshaft below 300' duration. **Technical note regarding late-style dual valve springs: -These HD-Single Springs are nearly identical to the spring pressure rates of the dual valve springs found on the late M30 heads made after 09/1986. This means that this is an inexpensive replacement option for those springs. No additional hardware is needed. Made here in the USA.