The 305HO heads are decent heads, but they are not copies of vette heads. They use a smaller intake valve, pressed in studs, etc. I can't seem to find any specs on either except that the HOs have 1.94/1.50 valves. [This message has been edited by Chevy408 (edited 12-04-2001).]416 Main Street Johnstown, PA.Does honeywell thermostat have a reset button