I have a '91 Accord which has a burnt valve so I am removing the cylinder head and having a pro do the valve job. I am running into a problem with the engine coolant drain. I can not locate the engine block drain bolt but have drained the radiator of coolant. Do I definitely need to drain the engine block of coolant or is just a radiator drain good enough to proceed with the head removal? Thanks for the help

No need to drain the block.

Just make sure you remove any coolant that might get in a cylinder when you pull the head...coolant is poison to o2 sensors...