Unless the engine has major issues like worn main bearings, rings etc. If it's using large amounts of oil between changes or has a big loss of compression, otherwise I wouldn't look at putting another engine in it yet unless you have alot of money to spend. My Dad's 04' Z71 Tahoe has 245,000 miles on it, no issues, leaks and runs like a champ. We have another family member with a 96' Z71 that has almost 400,000 on it, leaks a little oil but it stills runs strong. Pick one issue at a time, diagnosis it with the help of a good scanner and go from there.
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