Yes I drilled the thermostat on my 261 with a 1/8 drill and also ran a 160 degree stat out here in Central Calif as out here it gets to 110 degrees at times. In the winter I ran a piece of card board across the rad to keep the temp at 180 degrees. This was with a 4 core Radiator and did not have any trouble with over heating.
62Blue
Don


62Blue
62Chevy in progress
You've never been lost until you've been lost at Mach3" Paul F Crichmore (Test Pilot)