Most of the issues are caused by a mismatch of thermostats with the Cleveland or by using aftermarket water pumps like the Wieand that do not have the bypass hole drilled in them.
I did have issues with the Wieand pump initially since I did not know about the lack of the bypass hole.
The car temperatures would radically cycle from cold to very hot and seemingly take forever to get to a steady running temp?
I stayed with the Cleveland thermostat, the stock brass restrictor plate and drilled the bypass hole in the pump.
The temperature is now predictable, rises as it should on the gauge.
The product description says that "leakage" through the original thermostat seat is bad. I disagree. It is there to reduce thermal shock to the engine.
There has been much discussion of this subject here on this forum. This new block off plate is a relatively unknown item.
I'm not sure if it's a good idea on a Pantera with the as delivered cooling configuration?
Using it, you could be into re-inventing the wheel with the Pantera? Why do you need to do that?
Over heating issue reputations are really caused by the early cars, i.e., the '71s. By the time you get to the "L" cars, those issues were corrected.
If you feel that is hog wash and want to reinvent the car, have a good time, but it's not necessary.
A stock L will run in the Phoenix/Vegas heat with little issue at all.
With a 50/50 ant-freeze mix and a 16 pound system where the cap works, you are good to over 250 f of water temp before it boils over. 254 I think is what the chart shows? People seem to freak out when the car gets to 212 for some reason? It's supposed to. 220 would be a nice running water temp and 220 to 230 for oil is good. You have to get your oil over 212 to boil off the water contaminants. Cold oil will also cause more wear to your engine than 100,000 miles will AND it contribute to parasitic loss of horsepower internally in the engine. Race cars now use oil heaters to bring it up to operating temps.
Honestly, I'd be getting nervous around 240 water temp. That's where the car is getting hot.
If you do anything to the car, go with Halls brass radiator. It has a 50% greater cooling capacity and can be repaired vs. the aluminum radiators that when they hole through, and they will in a couple of years, are done, those you throw away because they are not repairable. They are usually rotted through the aluminum then. The aluminum radiator is not the way to go on this car. The ONLY advantage it has is weight savings.
Just my perspective. Others here have different opinions.
