For the last five years, I've daily driven a 2011 CVPI SAP. It's an old cop car with 120k miles and 7000k idle hours. While the motor is pretty clean internally, recently I noticed a ticking and traced it down to a failing rocker barring. It's not super loud but definitely audible with a stethoscope. No scarring on the cam yet, but without replacement it is destined to become a bigger problem. Here's my pickle. A few days ago, I took off the valve cover and put it back on without touching the lifters or rockers. I have 4 of each sitting in oil. I ended up breaking off a valve cover bolt. Not a big deal, I have a tool to extract the broken bolt. I ended up dropping a nut down into the oil ports leading into the block. I'm hoping it will go to the bottom and I can fish it through the oil drain plug hole. The nut was 10mm and drain plug hole is 15mm I think. Here's my thing though, I know of a couple junkyards with motors out of civilian Crown Vics and Town Cars with less than 50k miles on them I really don't want to lose power, but I would trade power in for longevity any day. One motor is a 2010 Town Car 4.6 2v with 47k miles and they want $750 for it without core. And the other is out of a civilian Crown Vic with 51k miles on it also without core. I've talked to a couple of mechanics and swapping the engines is definitely doable and it would cost $800 to $1,000 just to put on in. I just worry about if I fix my original engine, what is next? Timing chain, more lifters and rockers going out or worse. Also, the tranny is the same deal. While it works now, it's still and old cop car and might lose a gear any day. More and more headache. Or should I just put a good used engine and trans in it out of a civilian car. From the math I'm looking at, I'm looking at $3k or less to do this. Again, if I fish out this lost nut, fix the broken bolt, and replace the rockers and lifters making a noise, what is next and how much will it cost in the long run? Meanwhile for about $3,000 I could have a brand-new Panther. I need comments from old school mechanics and guys who know what they're talking about here.