To “properly” install those springs, the heads have to come off and machining is required.
Additionally, the ID of the inner spring is quite small.... so the guide will also need to be machined to facilitate the use of seals with a small enough OD to fit inside the inner spring.
If the heads currently have exhaust rotators, and 2 groove exhaust valves, the valves will likely have to be swapped to the four groove(or single groove) variety so you can get enough installed height, and the rotators won’t be used.
Aftermarket retainers are recommended.
