What is the biggest shot I can run through a mostely stock 5.3 with 30,000 miles on it? Other mods include a set of true dule 3" flowmaster, a Mac intake with 3" stainless steal tube, and diablo tuner. Also is it safe to run spray with the diablo tuner ,and what is the best kit.

 

I'm not sure what the best kit is, but it dependes oh how much you are willing to spray/pay. The NX wet kit is a proven kit, and there are people spraying up to 150 shot with it. TNT seems to be popular with the f-body guys, and Cold Fusion has really good prices.

I personally prefer wet kits, but their are some that can run the times safely with the dry kits. As far as what the stock short block can take, I think the jury is still out on that one. People have sprayed 200+shots and others are boosted with 50+shots.

 

Nothing is safe, but...

You could run a dual stage system and hit the lower rpms with a smaller shot, then hit the upper rpms with a bigger dose. Say a 100 shot from 300-4500 then another 100 on top.