The rad is about 3 1/4” thick, 2” space between rad and fan, clutch fan is about 3”. So you have a good 8” to work with.
The back of the engine is 1.5” from the firewall and the overall depth of the engine bay is 41 3/4”
Some math and you can figure what you have space for. I don’t think a 53 is as deep
bet that was a good feeling. hows she run?