No, the lite-muffler is the untuned muffler used on the 3D/profile, some scale, and the control line engines. (shown on BSE-76L below)

The black muffler refered to is the muffler supplied with the AMA 428 Q-500 engine - just like the red jett-stream muffler - just shorter, and well...... black Slightly lighter, and tuned for over 19,000 rpm.

No specific part number on this (although I should add it.. ) Just tell Dub you want the Q-500 black muffler to try on your SJ-50 engine.