ok well i just bought a set or ARP head studs just the normal ones not the 625's but i am eventually going to be running twins. the guy i bought them from said you dont have to bottom tap the block but that contradics everything i have heard about them. also he said fire ring the head but i dont really want to fire ring cause there a pain and you have to constantly retourque i was thinking o-rings but he said he wouldnt trust those? he claims he used to work for industrial injection and built all of there race motors. also he said that with the 12mm VE i wont be able to spool the he351/ht3b compound set im going to be runnig i think that it can be done but i would like some intput on all of these as i am going to be building here soon.