Is a 4.8 a straight bolt in for a 5.3, wiring and everything? I bought my burb used and it had a blown engine. The car dealer had replaced the engine. I want to make sure I have the 5.3 and not the 4.8. Of course, if I do have the 4.8 I'll have to live with that. It tows my travel trailer OK. Won't win any races..