radiator
Check that link out Rob.
You can see in the pictures of 455bird radiator. Then Busasandrail shows a picture of his radiator. You can see the little weld line around the middle of the right side tank. That holds the separator in place.
Scince both coolant in and out are on the same side there needs to be a separator in the middle to make the coolant flow through the radiator.
455's buggy would get hot cause the little separator was missing or damaged and not forcing the coolant through the tubes. It was going in the top and flowing out the bottom with little to no cooling.