I have a 1999 Chevy Tahoe 5.7L just put a crate engine in
I was wondering what performance upgrades would be recommended that I put on it for more horsepower and the deep growl.
Don't know if a TRUE dual exhaust is possible? Up to you to decide what muffs / sound quality you want.
Most intakes, many cat-back exhausts, and shorty or mid-length headers are not really worth much power.
What axle gear do you have?
Normally I say 4.10, but the L31's redline is so low, 3.73 may be better.
Get your pcm reprogrammed so that the 4L60E is more responsive and fun.
If reprogrammed properly & thoroughly, the L31 can rev up several hundred RpM higher.
Then you can decide between 3.73 & 4.10.