It could have milled on a previous rebuild. This car was raced and hacked together to sell. They even restamped the block and sold it as matching number. It was milled again this time or the heads milled to get more compression the first time. Then you throw in a couple of valve jobs and the seats sink some. Then you have a cam with a slightly larger base circle. It all adds up to too much preload. I think lifters have around .060 preload anyway from the factory. I have not even checked to see if the pushrods are stock length yet. They could be off as well. I would not put it past these guys to pull the dowel pins out of the heads to slightly drop the head down enough to make the intake fit.