when i had my 59 built the engine guy gave me hydraulic lifters. i told him i wanted solids. he said he'd have to change the cam to a solid lift cam. after he gave me the engine back with the correct cam he gave me the lifters and they were solids but the milk can type. the lifters are the same od but the hydraulics and the solid with the annual are shorter thus the longer rods. there are two rod lengths 10 9/16th and 11 1/4qtr.