Mike.............I should have been more specific..........aluminum rads are usually 2 rows of 1" tube. I have forgotten about special 3/8" tube alum rads. There are and can be custom made alum rads. But most offered in Jegs or Summit are 2 rows 1' tube.
A 2 row 1"tube will measure 2" at the core.
When using a wider tube alum rad , you must be careful when running higher pressure. the pressure can ballon a wider tube and actually cut off flow to the tube on top and the one below.
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