You definately dont want cast iron pistons. They haven't been used since about 1900.
I personally would bet TODA pistons about .010'' and ARP everything.
Pistons: $1200ish
Block Machining: $200ish
ARP shit: $400ish
You also need bearings and gaskets.
98 should be okay depending on timing. Could run booster.
12.0:1 and nitrous is asking for trouble.
Revs should be fine up to over 8500, not sure about any thing over 9.