If ground cooling turns out to be a significant problem after this even is sorted out then maybe a Reno style spray system on the radiator would be an easier 'fix'?Replacing the lines would involve a major disassembly of the aircraft. Plus weeks if not months of time. Could we do it? Yes. Are we going to? No.
Engines can go a surprisingly long time overheated without damage, especially all aluminium engines.We will do another hot and cold compression check.
Any thoughts? Is the engine "cooked"?
Yes, plenty of space behind the radiator. Getting to it is another matter.Borescope it if you're concerned, sparkplugs out, camera in each cylinder will get you an idea on piston and valve condition.
As far as ground operations - got a little space behind the radiator? 1-2 electric fans would be able to get you the airflow needed. GM alternator wouldn't struggle to power them.
I would get the cooling good enough for any aerial use. For ground help, a water spray set up should be simple and fairly effective. A pound of water does a lot of cooling. It would be less restrictive than fans.Some kind of electric blower etc for temporary ground testing may be warranted. Permanently mounted fans tend to me more trouble than they are worth in-flight, causing more restriction than flow. Been tried many times.