I agree with Tim, but about the cars having hydraulics and trucks having solids originally, but I wouldn't trust the casting numbers to tell me what it should have. All 235 blocks from '56 up were drilled for hydraulic lifters. So, over the years, the original ones could have been replaced. It may take a little work, but I would pull one to remove all doubt, because hydraulics won't work with a solid cam, and solids won't work with a hydraulic cam.
