Would the injectors or the fuel pump on a 1999 5.3 meet there max first[make it run lean] running a large dry shot?

 

probably the pump, followed closely by the injectors. put in a 255 pump and run a wet shot IMO... much safer and easier to tune.

 

Injectors will. Get 255 intank fuel pump and injectors and then your motor will go before you run out of fuel.

 

Yup our 99's had tiny *** injectors(19lbs). I have some 31# injectors for sale in the classifieds....

 

How do you know what size injectors to buy and where is a good place to get them?

 

My injectors maxed first. You can get a set of stock 8.1L injectors for $100 or less, just look around. They will be more than enough for your setup. You will have to get tuned for an injector upgrade.
Also, +1 on the 255 fuel pump swap.

 

How much of a dry shot would you think it would take to max out the injectors or fuel pump?[1999 5.3]

 

50 ish, I'm maxed out on them with just a cam swap.

I have some 8.1L injectors I'll sell you. $110 shipped.

 

probably like 100 dry on stock 99 injectors with boltons only. But with some 8.1 injectors and 255 fuel pump you could spray 150+ no problem.

 

damn, I forgot the 99's had the smaller injectors...