Relax al is normal Srock big block heads all the exhaust bolt hole go into the water jackets.
some ways to deal with this:
1. Use studs IF you can.
2. Bolts make sure there is penty of threads going in to the head use a sealant. I use arp thread sealent you can use teflon tape Silcone etc..
It works best If you drain the block to below the bolts holes and let the sealant dry over night.
Also if you every play with a small block on stock LA head only the 2 out bolts go into the water good luck and get her sealed up