5.3L v8 replacement in a 2001 silverado

The compression issue could be a head gasket , either way you're looking at a can of worms , intake gasket could be worn , IF I had the money I'd invest in a partial restoration , How's the frame , brake lines , fuel lines ? But I don't like any newer vehicles , too much tech. you don't need , flip a coin .

You might consider a warrantied used engine if the rest of the truck is in decent shape. the other stuff is considered normal wear and tear. If your still considering a new truck I would wait until the prices come down, everything is crazy high right now

Most likely the low compression is due to a worn camshaft. A common problem with GMs. The vehicle is 21 years old. If it were me, I'd replace the vehicle with a newer one. Replacing the engine might seem like the cost effective way to go on the surface, but the rest of the vehicle is still 21 years old with 187,000 miles on it. You already know it needs a fuel pump and front end work. How much longer before it needs transmission work? Plus, when you replace the engine all the wiring, air conditioning components, power steering components, vacuum hoses, etc. need to be moved out of the way. Most of these things have not been touched since the vehicle was built! Wiring becomes brittle, the same with hoses, fuel lines, etc. things will crack and break just moving them out of the way to get the engine out and the new engine in. I think if you replace the engine you're going down a rabbit hole of never ending problems from this point on. Hope that helps! Jim