need help with plug choice

just got done building my 408 sbc and need a little help picking out a plug to use in the car. here is what the engine consists of

408 sbc
eagle crank
6 inch eagle h beams
kb 128 pistons
Dart iron eagle platinum 230 cc heads 2.08 1.60 valves and isky tool room springs

bullet racing 645 645 solid roller 276/284 dur on a 106 tucked in at 102
7/16 1.5 scorpian roller rockers
Holley keith dorton intake
AED Holley 750 ho modified carb
csi electric waterpump
double roller timing chain
msd digital 6plus
Mallory HEI Dist (swaping to a msd pro billet)
5500 nitrous converter
Th400

need a little help picking a plug for tuning and then a plug to run it with

thanks for all your help

tony