TMR0027 is a downflow radiator for the Mack RD, DM.
The core measures 29" high by 34.25" wide, 0" deep. It has a 2" inlet at the left and a 2.5" outlet at the left. The unit carries no integral oil cooler and a top filler neck.
It replaces 7 OEM and aftermarket numbers, among them 730029, 730029BT, 621RA029. Searching any one of them will find this part.
On radiators the inlet and outlet positions, and whether the unit carries an oil cooler, decide interchangeability more often than core size does. Two radiators with identical cores are frequently not interchangeable.