All Small Six Valve seat inserts into a log head

[Dcsme]

Hi there, I'm currently in the process of reconditioning a 221 (aussie falcon). I've read to be careful when machining the head for valve seat inserts. I'm planning on fitting exhaust insert only. How deep is safe before entering the water jacket?
Look forward to some advice please.

 

[CNC-Dude]

Well, that is really defined by how thick the valve seat insert is. You should try to find the thinnest one for that valve size as you can just to play safe....