I had this choice to make when I got my '01. I knew the chain guides were shot at 260k miles. It still ran pretty good, despite the blown headgaskets, but I knew it was only a matter of time. My plan was to do a refresh on the engine while I had it out. However, I soon realized that a refresh wasn't going to cut it. At tear down, I found that coolant had been sitting in a couple of the cylinders and had ruined those bores. (The truck had sat for about 3 years when I bought it due to overheating from the leaking t-stat housing, which was the root cause of all the problems, except the chain guides.) There was also a lot of rust from condensation in the rest of the engine, cams, oilers, etc. My options were a complete rebuild or a reman engine. I chose the rebuild, since I could do it myself and would know exactly what I had. The only moving parts in my engine that weren't replaced with new parts were the crankshaft, jackshaft and rods. All in, I probably had around $3000 in the rebuild, including machine work and all of the new parts. I never actually added it up though. Could have been a little less, possibly a little more, but that was before adding the supercharger. LOL I did buy forged pistons in anticipation of the SC.
My truck was in pretty good shape for the mileage and the age, which is why I chose to give it new life. Had it been a rust bucket or beaten up otherwise, I might have scrapped it or just found a decent used engine. As it is now, I would have no problem driving it across country if I needed to. Luckily, though, I have other more suited vehicles for that trip, both in comfort and fuel mileage.