built 5.3 questions with sound video
 

Hey guys recently got my build done.
Stock heads ported with 2in s6 valves
4.8 flat tops
Clevite h main and rod bearings
Mls head gaskets
Custom grind cam 572/566 218/221 115lsa


Anyways sounds great haven't got it ironed out yet
Question is do you think I will need an injector upgrade?

Video

sounds good, almost what i was going to do but i dont have a cam, yet.

What year engine, was it Flex Fuel compatible? Some of the earlier (99-02) engines had mosquito feeders on the fuel rail that barely moved enough fuel to keep the engine alive. If you have the 36# injectors (Flex Fuel) then you're golden. If you have the 22 or 24# injectors, you're golden brown with a touch of crispy piston.

It's an 01 engine non flex fuel. The reason I am wondering is because before I had a tune can and longtube headers and it was faster and pulled harder than it does now. Just looking for some insight on what it could be.

I'm guessing you haven't had it on a dyno or hooked up to a wide band to check the a/f ratio? I would make a few pulls on the street and read the plugs at the very least. And hooking up a FP gauge and tape it to the windshield to see if the pump is up to snuff much not be a bad idea either.

did some tuning on it with the hp tuners laptop. fuel trim is showing lean. plugs look lean to me. yellowish tip. guy said i need better injectors. just curious i see all these 370-420hp 5.3 builds but never hear anyone say they put injectors in them? just wondering how they are doing it.

they probably run them over 90% duty cycle

the calculators online say that for 400hp flywheel at 80% duty cycle you should need about 32lb/hr

duty cycle was at 115%

at like 4000 rpm