When you pull the cylinders, avoid possible piston ring issues (during cylinder reinstallation over the piston) by pulling the cylinders just enough to expose the piston pin. CAREFULLY remove the pin circlip and the pin. Highly recommend you stuff a few paper towels into the engine case bores to prevent a circlip from flying in there. You only need to remove the one circlip on the side to which you'll be knocking out the pin. Once the pin is out you can remove the cylinder and piston together. This way the rings stay in place with no risk of breaking one when re-compressing them for cylinder replacement.
I'll add that you potentially could leave the base gasket alone if you were simply doing the heads and not doing the lower head studs. But it's indeed a risk. My first top end job around 15 years ago in 2006 was on a very nice '87 3.2L. It had moderate mileage of something like 68K miles and a rust free car. I share those details simply to substantiate how I got EXTREMELY lucky in the following ways:
1. None of the base gaskets have leaked since the work was done and engine has 20K more miles now in 2021. It's driven plenty hard and often. I had the car from 2000-2014 and the guy I sold it to is a very close friend who drives it like he stole it.
2. I found no broken lower studs upon disassembly (wow those nuts SCREECHED coming off) and i'm shocked that a dilivar head stud didn't break during disassembly, reassembly or since then. This thread got me wondering what method I used to torque them in reassembly...........
I think the lack of leaking base gaskets in my case is just dumb luck. They may show some weeping now but certainly no legit drip leakage. I also think the survival of the head studs is from the car rarely ever seeing inclement weather and never being in horrible salt-tainted winter weather. That said, it irks me to this day that the engine still has those annoying dilavar studs in place.
Point of me sharing is not to endorse leaving the base gaskets. Just sharing my one example of luck. When I tore down my most recent engine repair job, an '86 3.2L in late 2017 that's been in my family of friends since 1999, it had more of the common issues I would expect to find. Nasty valve guides (cyl. #3 so bad that the oil was washing the combustion chamber clean- not covered in carbon like others) and one broken lower stud.
Number 6 cylinder showing typical carbon on the piston and note the missing end of the stud on the bottom right
Number 3 cylinder with piston washed clean of some carbon due to valve guide leakage (and maybe a leaky fuel injector too?)
Note the pool of oil sitting in the number 3 intake port
Number 3 head with a very clean combustion chamber
Number 6 head with typical carbon buildup in the chamber
Number 6 lower, outer head stud broken and bouncing around in the cam housing
