Y2K_Frenzy

I recently bought a stock ‘00 Z28 with 27k miles on it. This is my first venture into the GM world coming from the pushrod 5.0 Mustang world. Where is the performance “bottle neck” with the stock ‘98-‘02’s? For example, with the old 5.0 Mustang the stock cylinder heads were/are the restriction. The stock exhaust system could support around 300 hp (motor) but it only made 220 hp with the stock heads. So until one changed out the heads there was little power to be had by bolt-ons, intake or exhaust. Cam swaps with the stock heads is only worth 10-15 hp in the old Stangs.
What’s the skinny with these? What’s “holding them back?”
How much power can the stock exhaust system support? Or is it at is limit already?
Cam swaps- Are they worthwhile without changing the rest of the top end?
Would a tune on a stock auto car be worthwhile just so one could have the ability to change shift points? Sorry for the newb questions and thanks.

LLLosingit

iTrader: (4)

Most start with the usual Cam, Intake, long tube Headers. Combined they offer the best bang for the buck, Heads would be the next step.

Cajun ELESS-ONE

Heads and intake (if it's the ls6 intake) flow well. The ls1 can make really good power pretty cheap. This site has alot of information on proven combos. Start with bolt ons. Longtube headers, ypipe, catback. Higher stall if auto 3200-3600. Gears in the rear(3:73 if auto 4.10 if 6speed) Good tune after with some good tires will give you a car that could easily get you a very quick car(mid to high 12 second 1/4 mile time). Add a midsize cam 226 to 234 duration 600-610 lift with supporting mods could get you high 11s in the 1/4 mile. I'd say the choke points will be the weak links diff if it's a 6speed trans if it's an auto. Some suspension mods are always good. I'd do those before the cam.

01CamaroSSTx

iTrader: (3)

H/C/I with some LT's and a good tune but be advised...The rabbit hole can sometimes be deep and you'll find yourself in there.

Y2K_Frenzy

Yeah man, I know it. I’ve played the hotrod game before, if you upgrade X part you’ll also need Y and Z, and somewhere along the way something is going to break. If you didn’t have leaks before you opened it up odds are you will after you do at some point as well.
I’m not looking to make this one a drag strip warrior, I don’t want to thrash on it that hard. It’s way too clean. This one is just going to be a pretty day cruiser but ideally I’d like it to be able to run with the “modern era” stock’ish Camaro SS, Mustang GT, etc. Would it take a full H/C/I to not get blown away by the new “entry level” V8’s from say a 50-100 mph run? Or would a cam swap suffice? Mine is an auto with the 3.23 gear and I don’t plan changing it since I’m not really focused on hundreds and tenths of seconds so much. I’ve had 3.73’s in another car in the past and it now has 3.31’s.
One more ridiculous question. Just how restrictive is the stock exhaust? This is one thing that I’m really on the fence about it. As crazy as this sounds (no pun intended) I kind of like the quiet. I have a loud toy, and to be honest it gets old after awhile. The stock exhaust on the Z28 sure was nice on my 700 mile trip home with it. Are we talking like a 15-20 hp difference between stock and “full exhaust” with stock heads and maybe a 20-30 hp difference on the H/C/I car?
Thanks again.

Roarin_8

iTrader: (5)

Looks like you have an auto, first mods should be a higher stall torque converter, trans cooler and drag radials. Those mods will really wake the car up while keeping the drivability the same once under lockup.

Y2K_Frenzy

Yeah I have an auto with the 3.23 rear. I’m not looking to make a drag car out of it though. (If I was I’d skip past the DR’a and just get some slicks or maybe the MT e/t streets). So I’m not needing or wanting to launch at higher rpm really. But I’d like it to be quick enough to not get blown away by the new 400-460’ish hp street cars on the straight away of a road course type situation. So I guess more power from a roll is what I’m after. I realize that a “good” drag suspension, high rpm launch, and sticky tires can make a lower powered car run a faster e/t than a car making mower power that doesn’t have the sticky tires etc. But I want to be able to keep up with the new kids from say 50-100 mph. This is all theoretical bench racing of course. I’m not going out looking for races. It’d just be nice to know that you don’t have the smallest piece when you’re standing at the urinals. Know what I’m saying?

Roarin_8

iTrader: (5)

I don't have a full drag car however I'm telling you right now, a higher stall torque converter is NEEDED if you want to race from a roll. The shift extension will make a world of a difference and leaving from a dig is a completely different feeling from stock. I've been running drag radials ever since changing to a different converter since street tires were useless. Was daily driving the car at that time too, work from home now and hopefully it will stay that way.

RPM WS6

iTrader: (3)

A higher stall converter is not just about drag racing (launch), it's just as important in roll racing due to the shift extension improvement mentioned above. If you're buying a quality unit (do NOT go cheap on this) then even at ~3500 stall speed it will drive pretty much like stock at part throttle with 3.23s - most folks are used to the slight part throttle looseness after about a week or so of driving. Once you're at lock-up speeds it drives exactly like stock (such as on the highway)...until you go WOT.

Other than N2O or FI, there is no one single thing you can do to better improve dig or roll acceleration potential for an auto LS1 than a 3500+ stall speed. The best advice I can offer is to NOT overlook this modification if you want a BIG improvement with very few downsides or complications - but, again, DO NOT go cheap on this. Quality makes all the difference, both in terms of gains and impact on driveability.

Roarin_8

iTrader: (5)

Yup, plus you'll need one anyway if you go with a bigger cam.

Y2K_Frenzy

Thanks y’all. This is my first venture hot-rodding an auto so I have bit of a learning curve. I haven’t tried it yet, but will it let you foot-brake it? My DD’s will not let you. The ecu cuts fuel (assume fuel) before the tires even consider moving. I’m assuming as a nanny to protect the transmission. Do you have a converter recommendation?
What’s the way to go for the transmission, a shift kit, a “tune,” both, or neither?
Speaking of tunes, what and or who do y’all use? Dyno or handled & data logging etc?

wannafbody

iTrader: (2)

4L60E, 10 bolt rear and your credit card limit

99 Black Bird T/A

iTrader: (4)

Welcome to LS land and the forum!

Honestly, coming from push rod 5.0 Ford's, a lot of this will look familiar.

For an automatic LS F-body, quality high stall torque converter is #1 mod as mentioned above.

The biggest bottle neck is at ~450whp as the factory fuel injectors & fuel pump need upgraded. It pretty easy to make 425 whp to 450whp with excellent driveability.

Otherwise, it's easy to make power with the following items. A few rough estimates.

1) basic bolt on's like aftermarket lid, 85mm MAF, 92mm TB, 92 Fast intake, long tube headers, dual exhaust. ~ +45 whp to +60 whp depending details.

2) any good medium cam ~224/230 to ~227/235. Should gain ~45 whp to ~55 whp . Add under drive pulley for good measure

3) Ported cylinder heads, aftermarket heads or ported aftermarket heads can add ~20 whp to ~50 whp depending details etc.

NA ~450 whp is doable with out breaking the bank. ~500+ whp is possible but tends to get very expensive NA with an LS1/LS6. Stock crank is very durable 1,000 + hp. Stock LS1 pistons & rods are pretty good but not as durable as the crank. Time has show pretty much any year LS can spin ~7,000+ rpm without issues with a stable aftermarket valve train. The stock LS1/LS6 oil pumps have cavitation over 6,000 rpm, ported stock or aftermarket helps reduce issues etc.

4) Power Adders, Forced Induction - turbos & supercharger or NOS: Sky seems to be the limit with expert tuning. Stock bottom ends seem to live pretty well with excellent tuning ~600 whp+

Roarin_8

iTrader: (5)

Yes you can footbrake it, in the video below, I footbraked it to 3500rpm which is why you see the rear pop up...better to preload the suspension anyway. I went with Yank with no complaints, you can also check out the automatic section to see other converters that members went with. I didn't have a shift kit put in and had the trans tune for shift points and lock up with HP tuners. Make sure to get a trans cooler though, extremely important! Hope that answers your questions.

01CamaroSSTx

iTrader: (3)

It'll take 500-600 rwhp to hang with some of the factory performance cars today.

Roarin_8

iTrader: (5)

Those new cars are HEAVY though, 600rwhp in an fbody, looking at 130mph traps at least.

01CamaroSSTx

iTrader: (3)

Yes indeed!

Y2K_Frenzy

I think the new Camaros & Mustangs are around 3500-3600 lbs or so. The Dodges’s are heavy 4k pounders though.

Roarin_8

iTrader: (5)

The V6s are around 3500lb range the V8s are in the 3800 to 4100lb range and that's without the driver. My Fbody weighs 3365 without me in it.

Y2K_Frenzy

I stand corrected.