I started having some heating issues with my CR about a year ago. It's 20 years old and had a brass/copper 4 core in it. I replaced it with a custom aluminum from Mattson's Custom Radiators:
Mattson's Custom Aluminum Radiator Chevy Big Block | The-Fan-Man spal fan manufacturers, electric automotive cooling fans
They built me a multi-pass radiator that was the same size and same mounts as my old Modine. They added a shroud to hold a large Spal electric fan and the whole thing I thought was reasonably priced.
The only issue I have now is it takes forever for the coolant to warm up on a cold day. No overheating problems at all
