I have a 1989 Mack with an EM-6 300 that spun a bearing and the piston hit the head. It looks as if the heads are ok but crank is to bad to be turned. From talking to my mechanic it looks like best case scanero 6-8k on rebuild.
Ive had several local "Mack Guys" tell me I should not put that much money in an E6 engine and I should upgrade to the E-7. Also the E-7 comes in a 400 HP which I think if I upgraded that's what I go to. I realize the E7 300 & 350 both can be turned up to more horse power.....my question is this.....what exactly is the difference between an E7 300, 350 and 400