Slo 6.0

Hello everyone I am new to this so if I mess something up I’m sorry lol. I have a 2005 GTO that is a 408 Stroker with a F1A-94 blower. I recently switched over to e85 and upped the boost from last year. I got it tuned and everything was looking good until we had a serious lifter failure don’t know if this happened while he was tuning it or just out of the blue. I tore the motor down and put a set of Johnson link bars in it and the same exact cam. I remeasured push rod length and bought the correct push rods for the setup. Now out of no where I have what seems to be a misfire during load and hard acceleration. Happens at idle and in gear. Tranny is a built TH400. Now could this be due to the lifter failing during the tune? I have replaced everything as far as plugs,wires, and coils. Still no change. Any input would be much appreciated