@rene4406 posted:I visited the FlowKooler website and, If I understood correctly, they say the 333 series is made for the OEM bypass plate but only available in 180 and 195°F and indicate 11/16'' diameter; it is only if you want 160°F that you have to choose the "substitute" which is in fact a 330 which must be installed with an "alternative sized by pass" but without specifying the diameter, just "alternative sized".
FlowKooler would therefore sell 333-180 and 333-180 SUB which would be different and Summit would sell 333-180 under the reference 333-180 SUB????? So the error would be more at Summit than at FlowKooler?????
UPDATE ‼️
Rene hit the nail on the head. The description at summit ending with SUB is confusing and incorrect.
as Rene and Mike Drew have found, ordering that thermostat from summit does result in receiving the correct OEM high flow Cleveland thermostat
I called and spoke to a flowcooler technical representative, who understood the Cleveland cooling system.
for unknown reasons, they only have the Cleveland 333 series in 180° and 195° versions. Therefore, to supply a 160° thermostat (which is too low for all but maybe a dragstrip engine), they used a 160° Windsor thermostat and made their own bypass plate.
as for the hat diameter and the bypass diameter resulting in a permanent coolant flow, even when fully “closed”. All other Ford small blocks accomplish this constant coolant recirculation with an external hose.
I still think the best source for a correct 333 series Cleveland thermostat is Tim Meyer, who invested this time and money to keep them available after Robert Shaw temporarily discontinued them.
Larry