3RZ Burnt Exhaust Valves

I have reason to believe I have at least one burnt valve.

One of the valves has gone from .04mm to 0.2mm clearance over the last couple of months (originally it was at 0 but I swapped some shims around). The proper clearance is .25-.30mm.

What I am trying to decide is whether to rip it all apart and replace a couple of valves or replace the entire head. I don't think it is cracked but I have no way to tell until I pull it off.

Has anyone had luck with replacing a couple burnt valves, without having to rebuild the head?

If not, can anyone personally recommend a good source for a new head. I don't want one from china.

Thanks

 

I ordered the correct shims for now. Going to pull the head in December