One commonly overlooked necessity for efficient heater core cooling is a shroud, which is simply a device that acts as a standoff between the fans and the radiator. Standard case fans produce a dead spot in the center of their surface, so a shroud is needed to produce even airflow across the fins to maximize efficiency.
A shroud is very easy to construct; it can be made out of cardboard, sheet metal, or any other spare material you have around. One of the easiest shrouds to make for a '77 Bonneville core is a modified disposable food container. Simply take a spare CD, trace two outlines on the container and cut them out. This will leave you with two holes the perfect sizes for 120 mm fans. Just mount your fans to the shroud with screws, and then attach the shroud to the radiator with duct tape. When creating your own shroud, make it at least an inch thick; the greater the distance between the fans and the surface of the radiator, the better.
Here are some common radiator solutions
- Heater Core
- Black Ice