None of the cam companies manufacture flat tappets. They buy them.
The lifter on the left is made by Stanadyne, and is what Comp sold under part number 821-16 for years. They are a one piece "solid" lifter...... And they're heavy.
The lifter on the right is made by Hy-Lift Johnson, and used to be what you got when you bought 2921-16. They are a multi-piece design and are lighter than the Stanadyne part.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
