Good day all. Brand new here. I've come for a 2nd or 3rd opinion.

2007 Ford Mustang

4.0 V6, 5 speed manual, about 165,000 miles.

A month ago, I was driving this car and the engine just quit. It had been starting and running well up to that point. After the event, it was crank, no start with no unusual noises. I got the car towed home and attempted troubleshooting. Code scanner threw up a *pending* P0340 Camshaft Position Sensor circuit A. The data showed about 40 psi fuel. I could hear the fuel pump startup, but also checked and reset the inertia switch. 

I threw some parts at it - camshaft and crankshaft position sensors - though the old ones tested well. 

I gave up and got it to a (not my regular)shop. They came back with compression problems. 3 cylinders with 0, 2 with 140, and 1 with 70. They declared the engine wrecked and needed to be replaced, guessing that a timing chain jumped. 

With what I know, this seems plausible based on the outcome. It's an interference engine.

A little history. I replaced the engine in fall 2022 due to a timing chain cassette failure on startup. Supposedly, that engine had about 110,000 miles. June this year, the same timing chain failure occurred on startup. The same mech who replaced the engine was able to replace the front timing chain as no further damage had been done to the engine. 

I consulted with my regular guy and he said failures like that typically don't happen when running, mostly on startup. I'll ask the questions here that he didn't answer.

"Unless there is something these guys are missing, My intent is to sell it as 'needs engine'". 

If there is something that could be done apart from new engine, I'd rather try to sell it as "running"."

Is there something that could have been misdiagnosed by the first shop? 

Thanks for your help!