What I have is an 81' EM6 285 which started life as an intercooled motor. A few years back it was put into a glider and switched to aftercooled. The turbo and injectors were upgraded, but nothing done to the fuel pump and timing. I have been toying with the idea of dropping a 3406B into the truck which has had me asking a few questions about the component changes needed for switching an intercooled to an aftercooled engine. On a Cat the timing needs adjusted among other things for the change hence the wonder if my Mack engine needed timing changes. Thanks for any input.