IIRC the balance for the 318LA and magnum 5.2 are different. both internal balance and very close to the same but magnum rods are thinner small end/lighter.
I would use the magnum replacement flywheel from advanced auto for 130$ I replaced the one on my sons 94 5.2 magnum/NV3500
this will be correct for the 5.2 engine. BUT! you might get away with the LA flywheel and not FEEL the vib.
next is the magnum pilot bearing.
my 88-d100 v-6/a535 5 speed hydro bell has 2 trans bolt pattern, one for the 8333/833OD/a535 5-speed and also has the NP435 granny 4 speed pattern. (it would not fit my 92-NV4500 5 speed)
the 82 mech bell should fit the magnum also running the magnum flywheel but use the newer magnum pilot bearing.
for hydro clutch are you piecing a cheap homemade set up with mech bell or going 88-93 hydro bell?
either way I suggest the hedman 79170 long tubes for it. I have a set of ram tubes on a 94-5.2 magnum truck and would not use them again, no where near the gain of long tubes in a 82 chassis.