#523 - LGTH: 31 9/16" - 19 lbs. Top Flange: 10 3/8" w. X 4 5/8" dp. Bottom Flange: 6" w. X 4 1/8" dp.

Western Star side frame

Top flange has 12 holes, 7 tapped 5/16" N.C. threadsand 5 drilled clearance for 5/16" bolts. Bottom flangehas 9 holes, 4 tapped 5/16" N.C. threads and 5 drilledclearance for 5/16" bolts. Five 1/4" N.C. threadedholes on each side of frame. Sixteen holes on back ofchannel, 9 holes are 3/8" N.C. threads and 7 are 1/4"N.C. threads. Two notches in side of rail.NOTE: Side frames are not interchangeable. Order leftfor drivers side and right for passengers side or pairs.