MSD ATOMIC CHEV LS THROTTLE BODY 90MM 4 BOLT # MSD2940MSD ATOMIC CHEV LS THROTTLE BODY 90MM 4 BOLT # MSD2940 When you run an LS engine, performance begins with the introduction of air into the intake manifold. MSD's new 90mm LS Throttle Body answers the need for a high quality throttle body with a mechanical throttle mechanism that bolts to most factory and aftermarket intakes. MSD went through the time and expense to develop a cast throttle body assembly in order to achieve a unique parabolic bore form.