All,
This is VERY important!!!! 
The thermostat at Summit recommended by Mike Drew (on the email list) is NOT the correct thermostat for the OEM brass bypass plate installed in a stock Cleveland!!!
This is the link shared by Mike:
You can visit the flowcooler website for more details, but I will give you the basics of what they have done.
In the Flowcooler website description, they share how they discontinued the 333 Cleveland-correct series of thermostats due to low demand. Once they found Pantera owner Marlin was machining the proper hat to add to the 330 series (making it a 333 series) and he was machining correct replacement bypass plates, flowcooler decided they would get back into the game and make their own money.
What is being sold by Summit racing is labeled as a SUBSTITUTE. It is called a substitute because it is NOT CORRECT for an OEM Cleveland bypass plate. It is designed to only work properly with a new bypass plate designed and sold by…..Flowcooler.
What they have done is taken a standard hi-flo 330 series thermostat (with no hat) and machined a proprietary bypass plate that is matched to the smaller piston found in their SUBSTITUTE thermostat. Note the suffix to the part number is SUB.
The two-part assembly is pictured below. Note how the piston is a very tight (too tight???) fit to their proprietary bypass plate
If you have a stock bypass plate and you install the SUBSTITUTE thermostat (with no hat), you will wind up letting too much coolant remain inside the engine block and not enough coolant being sent to the radiator.
The solution to this problem is very easy.
Order the correct thermostat from Tim Meyer, who showed the initiative and invested his time and money to provide the original and correct thermostat and he also reproduces the correct OEM bypass plate.
Flowcooler dropped the ball when they discontinued Cleveland thermostats, and now back in the game they have only served to muck things up with their redesigned bypass plate.
Please share this with all the fellow owners you come in contact with.
And do not recommend buying a thermostat - or bypass plate - direct from flowcooler, summit or jegs or any place other than Tim Meyer.
Larry
Sent from me using a magic, handheld electronic gizmo.
