273 hydraulic cam/pushrod/adjustable rocker combination.

Those don't look like factory rockers to me. Locknuts?

Also the pushrods for factory solid / vs hydraulic are different, wondering if you looked up the wrong dimension. I don't know what they are, offhand.

"If I can get to it" I had a running 318 using original 273 hydraulic adjustable pushrods and could measure them, later..............