What "tunning" are you doing? You didn't say if you are running a stock ECU on a modded engine or if you have a after market ECU and can datalog. I have over 115,000 miles on my original motor with a Apex Power FC, SX Enginering fuel pressure regulator, and Walbro 255lph fuel pump. I have broken rear ends and trannys but havent had a single problem from the engine even though I hard lanch it all the time and hit the rev-limiter constanly. If you blew your motor, its likely from bad tuning (ran it too LEAN).