I recently purchased a pair of lovely Black Ice radiators for my upcoming watercooled rig. I had very specific needs given the confines of the case in which the rig is going. However, if you've got the space and the skills, you can spend far less cash on a rad from a chevvy.

One such viable alternative that is readily available and easily modified is a heatercore. While there are many different models that can be modified to work in a watercooling system, one that has gained quite a following is the Chevrolet Chevette heatercore. More specifically, the heatercore for the 1986 Chevette, Fedco part number 2-161 or GDI part number 399069, which is approximately 6-1/8" x 6-3/8" x 2". The factory tubes are 3/4" and 5/8" which require some modification to work with 1/2" ID tubing used in a watercooling system but this modification is not that complicated and well worth it considering that most auto parts stores have this heatercore for around $22. Additionally, the tools needed for the modifications are fairly inexpensive and they are likely ones that most already have on hand.
The article also gets a mention because the caption for one of the images is "Optimus Primed". Great stuff! Read more.