Oil recommendations for 65K mile '99Chevy 454 Suburban

[cwilli01SS]

'99 Suburban 2500 with 7.4l vortec. 65,000 miles, runs smooth as glass but I have no idea what kind of oil its had. Any recommendations? Location is Georgia. Thanks in advance

 

[Drew99GT]

10w-30 in whatever brand you like. 3,000-4,000 miles for conventional, 5,000-6,000 for PAO or better synthetic.

 

[buster]

Here would be my choices. 1. Amsoil 5w/10w-30 2. Delvac 1 3. Amsoil 15w-40 AME I think these are all the top values in oil right now. Just my opinion. If this is a deisel engine, go with #2 or #3.