55.2-59 Going to need a new radiator.

[my56chevytruck]

Check out Auto City Classics. Bought mine to cool a BBC
100% Aluminum, 100% Welded Radiator- Lifetime Warranty

New aluminum, direct bolt-in radiator. It has a built-in automatic transmission cooler with 1 1/2" center inlet and 1 3/4" right lower outlet. This is stamped with welded construction, no epoxy.

Comes with 2600 CFM fan and shroud.

Has dual 1 1/8" high flow tubes, double the cpacity for stock 2-row, 33% more capacity then 3-row 1/2".

Core size: 17 3/4" wide, 20 3/4" tall, 2 1/2" thick
Overall size (widest point): 22 1/2" wide, 26 3/4" tall, 3" thick