I was reading about these engines wont last but 50k with 320 hp or more. Guy said hwe had a big turbo barring close to 400 hp and he blew it right around 50k. Whats the thresh hold for Hp/longivity with these? will they fall apart like the 302s did when hitting 350 hp plus range? How long (miles) have yall big turbo guys been running yours , at what HP?