300SDLguy,

You should have them put in the prechambers too. That way you will have ones that fit OK installed. I think I would go for a new head and make sure its a 17 or higher, preferable higher.

If you get a rebuilt head, also make sure it is a 17 or higher. Its the 14 that's the problem one. No sense putting on a head that might crack like the 14s do.

Ask Metric if they will use your valves and springs to save some money.

P E H