Looking for a miracle, Needing advice.

[drag1049]

Alright, let's start by saying it-- I'm really slow.

However, before a single number is thrown out, I'd like to gather other's guesses of what I should be running, so that I know I'm not crazy.

So here it is:
2000 RCLB Silvy 1500 4.8L with about 76k on the clock.
As plain as it gets, running on stocker aluminum 16's/30" tire combo.

Mods:
3.73s/posi - I hook flawlessly off the line, everytime. There is an advantage to not making power.
CAI - It sucks in air.
Yank TT2600, Vette Servo and Transgo HD-2 - Actually brake stalls to around 2300rpm.
Gutted cats - Used the old "they were plugged" excuse. Still on factory catback.
Nelson Tune - All TM removed, 87/89 Octane(gas was really going up, and I was really broke)

Race weight:
I don't remove anything(still carrying rear bumper and tailgate), but the truck is light to start with. It has absolutely no power options to speak of. There's nothing in the bed, and nothing inside when I race, other than my trusty 6-pack cooler bungee-d to the passenger seat, and me.
Soft tonneau cover weighs next to nothing, no weighty mods done, 1/4 tank of fuel and 145lb driver.(I'm a little shit)

So how about it, what kind of times should I expect?

Thanks.
-Matt

[RedHeartbeat]

15.6

[GMCwantsLS1]

16.0.

[Red03SilSS]

15.8ish. hIGH 15'S.

[drag1049]

Alright guys, appreciated.

I actually have yet to go 1/4 mile because I want a setup to have a chance at 14's first. I was thinking more like Red, that I should be closer to mid 15's(10.0 or 9.9 in the 1/8). However, I have only managed a 10.39(16.1/16.2) @ 68mph with my current setup.

This doesnt seem like a big difference(GMC guessed 16.0), but the reason for my frustration is that back in April, my very first pass with the truck was a 10.37, with only the cai and 3.73s, with a 2.35 60'. The only different condition was that the spare was removed then. My other passes have had similar atmospheric conditions because they were made later in the evening, so that eliminates the thought that it was the warming weather. My 60's now are slightly slower(2.38), as are my times and mph.

Quick timeline:

April: 10.37 in mid-afternoon heat
May: slowed to 10.6, installed converter and shift kit, saw same times.
June: slowed to 10.7, gutted cats and saw no improvement(hoping they were clogged, they were throwing a P0420 or whatever it is)
July: ordered Nelson tune, gained time back to around 10.5
My recent 10.39 pass had a strong tailwind on a cool, dry night.

So this is another sort of open question: Could something be degenerating simultaneously as I add mods, keeping me at the times I'm at?
This thinking was my reason for gutting the cats and cleaning the air filter, thinking either could be clogging. Maybe plugs or a tune-up deal?
I'm open to all advice, if there's something I should try/check/look for, or just get over it and keep spending cash.

Understand, I realize I'm not building any 12 second truck here or something, I would be thrilled just to tickle 14's, but I seem to be fighting a losing battle so far.

Again, thanks guys, I'm at wit's end here.
-Matt

[GMCwantsLS1]

I'm not saying it isn't possible, but you will have to do a bunch more mods and tuning to get to the 14 you are after. Best I could muster out of the stock 4.8 was 15.7 in a lighter truck than yours. What is the DA for your runs?

[drag1049]

I really need to start writing down the DA.
I know the track elevation is something like 634 feet, but that doesnt mean anything. I know its still gonna take more to hit 14's, but I seem to be fighting something right now that I want to sort out before I go any further.

[GMCwantsLS1]

You might want to get something to monitor the engine. Something to monitor knock. Maybe you are getting false knock and causing you to retard timing.

[whitesilvy04]

it's all good i'm pretty much wanting to run 14's in my 4.8L too... its possible just have to have dedication to see your way through it...

I would get a higher stall, Cam, headers and a new tune and see where that takes you and just work from there... thats what i'm doing thats just my opinion though so dont take it to full consideration