I’m running a cam similar in specs and I can’t get an idle I’m happy with. I didn’t realize I’d have to idle it at 800 when I bought it. I was thinking 700ish would do. From 700-800 it uses a lot more fuel at idle. Right now it’s doing ok at 775 but I’m taking it out and putting probably 10 degrees less duration. It’s a 227/234 in a 5.7 so if you’ve got that size in a 5.3 then I feel your pain