I am thinking, that you are thinking, ahead, about ten years for sure.

Most innovative 240 owners can push 300k or more, unless, a wreck happens, a thermostat sticks or a good deal presents itself. Forest Gump in the movie uses a couple phrases that sum up life pretty good for an ending to this thought.

Since you seem to be unsure that the engine is a straight up righteously solid, I might scrutinize the water pump more closely. Check the cooling jackets and freeze plugs for rock deposits with electrolysis in mind as past coolant abuses. These will bother the life of the head and the gasket more down the road. You can get horizontal with all of it out of the car.

Consider a head job only if the engine smokes oil upon startup or suffers from a bad valve or some other valve train issue. A working head gasket is on the bottom of the head and the list. In my opinion that is.

Those bolt torque procedures mentioned in another post, going in or out, when to change them out can be just as controversial as what about to do about all those valve springs. Bolts used twice and how many cycles are for springs. How long is the life for either, really! There are reasons for repairing something. Even then, you are going to hope that the parts and workmanship are as good as before.
Now, there is a box of chocolates!

I do know this.
Pulling a head off will not warp it. Heat can do that job, all by its lonesome.

The gasket in there will not have a problem as it does not have the moving parts. I have never seen this referenced as a “periodic maintenance item” on any vehicle. Doing another torque of head bolts after run in went out long, long ago.

It is fair to say that metal can exhibit its internal stresses before, during or after machining and then heat will change them again. Metal can remember those things during its “critical stages” of its molecular life. Metal lives in zones and we capitalize on them. Whenever I have machined metals or other materials, I give them the respect of rubber when just clamping them.

Strange thing for me is that, you never hear someone ever say “I warped a head when I over froze it!”
I have heard this though. “I took it apart and I think I put it all back together right, because I did not have parts left over.”

My answer was “I sure hope it was NOT a carburetor kit you using!”

Have fun, either way!
Phil