Info on exhaust manifold gasket fix?

[CCCC]

All of these old small and large blocks with high miles and have never blown or had to replace an exhaust gasket until now after a recent 4000 mile trip in 1972 C30 Motorhome - engine is 402BB with 108k miles. The leak is at the front end of the passenger side manifold.

I have purchased the supposed "heavy duty" (leaded?) Fel Pro gasket set at NAPA and am getting ready to go at it.

Are there any cautions about what not to do or any old tricks to make this go well? What should a guy use on the bolts to make sure they loosen properly without breakage? Any cautions about lining up the new gasket?

And, any ideas on why the gasket might have gone out? Should I be looking for possible manifold warpage after all these miles? Is there any chance that 1000 miles with a minor, but progressivly bigger, leak at that place could cause valve deformation? The outside air temps were warm.

Just being cautious on a first-time fix. Thanks for any info.