not sure of specs to tune a 350 bored 30 over dont know the year or what has been done other than what I was told, the guy I bought it from said his brotherm builds race cars and threw this in a chevy short bed 4x4 with 6" lift and duel exhaust, s... loads of horse power but pops every now and then and Im running high test in it . not a bad find for 500 bucks and a current sticker huh? so if anyone can help I would appreciate it