cross flow vs. up and down-aluminum radiators

use what fits.
the coolant has no clue if it travels top, to bottom,
or left to right.

Copper is actually a beter conductor of heat, than aluminum,
for the same size.

Aluminum is cheaper though.

USRadiator makes some good stuff. :)

http://www.usradiator.com/

http://www.usradiator.com/images/drawings/3/35245.gif