This is 1 x 1956 - 1963 Cadillac cylinder head 2 3/4” bolt. The measurements are as follows: 7/16”-14 x 2 3/4” the bolt overall length is 3 1/16” . Thread length is 11/16”. These will fit all models of 1956 - 1963 Cadillacs .These are good used original bolts, the threads are all good, there is nothing wrong with these. Sold As Is, As Shown.