I agree with klhanson and Green_98. The builders inadvertently installed the wrong gasket, not knowing the extra cooling between the cylinders needed for the 261. It would have overheated in the north pole given enough time.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum