New Flat Guide Plates & 3/8" Rocker Arm Studs Chevy sb 400 383 350 327 305 283 (3/8 Studs) Flat Guide plates Stud Hole Size: 7/16" Push Rod Slot Size: 5/16" 1.725" Stud height 2.425" Overall stud length 3/8"-24 Fine thread Top 7/16"-14 Coarse thread Base