If it were mine I think I would replace it with a complete rebuilt engine from one of the reputable reman companies.
I know its an old mechanics tale, that I never believed until it happened to me, but good heads on a old block can cause the rings to fail, in my case immediately.
Bill
I've had a lot of mechanics tell me the same thing...no use putting fresh heads on a high mileage shortblock. It'll be back real soon w/ more problems. Never had the problem myself, but never been in that situation either.
The Magnum heads are VERY prone to cracking b/t the seats. Saw very few of them come through the machine shop that weren't cracked. Now all of them weren't leaking water and hadn't all been run hot, but cracked nonetheless. No way to tell when or if the cracks would become an issue. And pressure checking a cast iron head w/ cracks like that will tell you NOTHING.
I'd get a reman engine and put it in.
