hello all.
happy seasons greetings!

Why is it that the front heater cores seem to have no problems?
I've examined the front and rear heater cores from one of my parts vans and
they are both made by the same french manufacturer. Both are the same
construction and materials, they are even the same thickness. they both
appear the original units, the rear is extremely corroded at the bottom
both sides at the steel crimp that holds them together. The front core
looks fine, as if it was getting different "long lasting
anti-heater-core-corrosion" fluid run thru it.
Is it just that the rear gets less circulation? Or could it be that it gets
hotter fluid thru it? I plan on modifying a rear housing to accept a front
core and front valve ( my typical cost saving measures... use it till it
breaks!)
I figure the only drawback is losing some under bench storage space. Anyone
gonna tell me some words of wisdom why I should shell out the $100 for a
new correct core?
                      thanks
                               David