1996 Chevy Tahoe changing engines

if you live somewhere where the temp is about 80+ all the time get 10w30 or thicker if its coolder you can do with 5w30 down to 5w15. if its relaly cold wher eyou live like freezing all the time or very cold you can use 0w30

10w30 i run no matter what the temp, its my recommendation.