Just curious what I might make.

Gen III 5.3 stock 862 heads
93 pump
head studs
mls gaskets
218/223 .571/.591 112+3 cam
.660 Btr springs
60lb inj
Magnum 76mm/.96ar
walbro 450 w/ aftermarket FPR
Meth injection (eventually)
80e
Efans
Stock intake
10bolt 3.73s (for now)

Say 8lb and I'd like to turn it up to 15-16lb once I get the meth on.

450'ish on 8lb and Is 600whp on 15lb doable? and still reliable in a DD? Granted I'm not going to be thrashing it 24/7. and it being a older gen III

 

Those numbers are doable 450-600 on 8-15psi! A good tune and you can see those numbers for sure! The only thing you're going to have to swap is those injectors once you start running more boost. I'm pretty sure 60#ers won't cut it in the 15-16psi range.

 

With the stock fuel delivery system they probably wont, but with a boost referenced FPR and walbro 450 I bet they will...

 

I see a handful of issues here. Certain things are a bit hazy. First of all are you expecting to run the walbro450 on a stock fpr? Also you mentioned a 76mm/.96ar. This could mean a lot of different things in the turbo world. Which turbo exactly are you planning on? So many different factors at play in any boosted setup. What rear end? What else do we know about the efficiency of this 5.3? What heads? Does it have efans I hope? Stock 78mm truck manifold? What rear end?

 

Those 60# injectors should be good for around 600-650hp i do believe. That's why I chose 60# injectors, since I know my 70mm turbo will max out around that same range.

 

How far the injectors can go depends on many other factors. Fuel lines, rails, pump, etc. 60# does seem a bit small for 600rwhp.

 

Sorry, yes it will have a aftermarket FPR.

It's a magnum 76mm

Stock long block with cam
Stock truck intakE
Efans
3.73 rear 10bolt

 

I have a stock bottom 5.3, 222/226 113+3 cam, head studs, walbro 450, 80# injectors and a magnum 76mm trick kit... its a little rich on 12# but my trap and weight add up to about mid 500.. I would like to get it on a dyno soon but that might help you out

 

Are they 60lb injectors or 60lb at our fuel pressure?

 

They are the Siemens Deka 60. Which I think are rated 60 at 43psi iirc? So like 72 at 58Psi?