Just off the top of my head, I would say in the 14.7 to 15.3 range with those mods, maybe better. The extended cabs are running in the 15.6 range stock and just aren't gonna get to where these reg cabs are with out more mods. Hell with all the mods I have on my 4.8, I still only run 15.5 in the 1/4 N/A. Before the electric fans, K&N (had AirRaid), and headers and the exhaust (I have now), I only ran a 14.6 with a 100 shot. I also know I have a rich condition on the truck right now. I need to port the TB and see if I can get that cleared up.

 

Greg:

Why don't you utry and reduce fuel pressure? Should be easier than porting the TB...not that you should de both <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Richard

 

Well, I was wanting to port it anyway, I've heard some good results from that, on the gars anyway. And I don't have a gauge to check the fuel pressure. Refresh my memory of how to do this properly w/o a gauge. I also need to get the time and make some A-tap runs when I do it.

 

2001 Sierra extended cab, 5.3, 3.42s, locking rear

If I get:

HPP3 or custom tune
160* stat
ASP pulleys
UPD intake
descreen MAF
change wires and plugs
true dual exhaust with x-pipe and hi-flow cats
ported TB

I can't afford to these all at once, but assuming I did, what performance gain would there be? Could I still run 87 octane with the descreened MAF and HPP3 programming? TIA

 

I have done all of the mods except the porting of the T/B, and I think this is a great way to get some good performance and a nice SOTP difference.
You might think about getting electric fans too. They are cheap and the install is not to hard. I used LT1 fans, but the LS1 fans work too.
I dynoed when I was basically stock. I had 2 flows dumped, K&N FIPK, and the PPIII. The dyno said 256rwhp, and 296rwtq. Since then, all the other mods have made a huge improvement. I will be getting a new dyno once the Hamms get on, but I expect to see 290-295rwhp and 325-330rwtq.
Sorry so long and good luck with what you decide.