40 Heater recore??

[hotrodA]

I had my 40 heater headed toward a resurrection until I found a miniscule leak in the center of the core.

Radiator guys x2 says it can't be fixed, but he can have a core custom made for only $250 or so. YIKES

So, can anyone (a) recommend a DIY fixit solution (b) a replacement modern core or (c) have a good used 40 core?

Or, do I find a heater core catalog and hopefully find one with same dimensions and change the tubes out?

Thanks!