As Jack says, it's really essential to check the head; I've done more L8 headgasket jobs than I care to remember, never found an issue related to the block itself though he's right, a "thorough" rebuild would resurface that as well.
You should have no problems if the head has a simple warp of perhaps 0.010" or so, the nature of the head gasket and gasket cement should accommodate that much. Beyond that or for more than just a modest warp, the head should be resurfaced but before you do that, not knowing the prior history of the head, you really must first determine how much can be removed before you run into valve clearance problems. One way you can do this, and it's been often discussed here, is to use a dab of modeling clay on the highest edge (remember, they are not perpendicular to the block deck) of each valve. Then bolt the head down with a used headgasket (one that has already been compressed), rotate the engine thru several revolutions (more than 2), remove the head and check the thickness of the modeling clay remaining. Don't expect the same clearances from front to back!
For newly inserted studs, I do use a "hardening" Permatex or plain old simple gasket shellac (Indian Head); I know this is contrary to other advice but I've never had the least of a problem removing studs that used the hardening gasket cement. For the gasket, I hang it by a wire a spray both sides with a copperized head gasket cement.
Go to final torque in 3 more-or-less equal steps following a pattern starting in the center and spiraling end-to-end and side-to-side. Very important - retorque within a few minutes of initial startup, again within a few hours, and at least once more. Checking torque as part of your annual tune or check-over is always a good idea.
This is a bit dated and should be cleaned up a bit, but still might be worth your time to read:
http://www.packardclub.org/forum/viewtopic.php?f=14&t=863This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=155437