Batten SB heads, leaking guides, fix?

We have old batten heads htat have some leaks in the exhaust guides. Is there any reasonable way to fix them, wouldn't like to throw tehm away because tehy flow very well and made good power.

R&R with proper O.D. press and seal with your choice of sealers. Correct the valve job afterwards. Simple operation.

Oversize guides, I had to make a set for a pair of 4V Cleveland heads years ago.

I've also heard that some has porous casting.