Rich,
Didn't you post in an earlier thread that the engine serial number ended in 54XA - 3600 truck 235? All 235 truck engine came with solid/mechanical lifters.
Did you ask the rebuilder to put in hydraulic lifters (or, had someone already converted to hydraulic lifters)?
Call the builder for a confirmation of what style lifers he used.
Good luck - you'll get this engine purring soon.