My ‘06 Silverado z71 5.3 is leaking oil and burning oil, cost of fixing leak is half the hours of replacement. My donor truck is a ‘03 Silverado Z71, 5.3. How do I make sure that this swap will work/fit before I spend the next few days doing all the work, and then come to find out it doesn’t fit like it should (a big waste of time and money) it’s my primary work truck, and I’m the only breadwinner in my house, so I’d sure like a little peace of mind it’ll be worth the efforts. Donor vehicle is my friends that got wrecked. I appreciate any input.

 

no can do. They are different engines. You need an '04 to '07 with the same engine RPO. And you need to post the vehicle VINs.