Yes, that is a Cummins part. The 4bt was developed by Case and Cummins. Your part was used on applications with a vertical exhaust system. Cummins part 3910992 is Case part J910992 which lists for $497.35. Wee bit of markup from the one you found for $50. LOL. Hagan Tractor Parts shows Case part A173623 replaces part J910992 or 3910992. They have used ones for $70 but the $50 is a better deal. When Case and Cummins ended their joint venture Case stated renumbering all their parts.