1997Z28

Hey guys i have a 1997 z28 6 speed im trying to figure out how i can get 400hp to the rear tires, any help would be greatly appreciated. I have already done
Long Tube headers
3inch ORY
No cats
Air pump delete
Egr delete
Tb bypass
160 stat
Cia
And its already been tuned.
My next mods was gonna be 3.73 gears &
Cc503 cam along with rr and heads.
Im not in a hurry to get there juat taking my time and doing it right. No spray lol
Any suggestions??????

ACE1252

The CC503, stock heads, and roller rockers will get you very close to 400hp at the crank(with long tubes, catback exhaust, and cold air intake).

A good friend of mine has an '05 C6. They have 400hp stock if I recall correctly. He has ran 8.3@88mph while I have run 8.3@89mph in the 1/8th mile(both of us on street tires and no crazy high rpm launch).

So I think that actually puts me maybe a little over 400hp at the crank since I'm most likely the heavier car.

If you are look for that at the wheels, you will need LE2 or AI head work with a good matching cam(good tune, right size injectors, etc).

bowtienut

iTrader: (1)

With a set of ported GM heads from LE or AI, you'll just barely make 400 SAE to the tires with the CC503 cam, depending on the attention to detail of your build and the condition of your shortblock.
Get a custom cam from either along with the heads, and you have to really mess something up to not make 400 through an M6.
I'd recommend 4.10 gears rather than 3.73's.

1997Z28

What does LE or AI mean? And I was thinking 373 bc it's still my daily driver as of right now.

1997Z28

Do you think that a cc503 cam be enough to get me to 400rwhp? And what is LE2

bufmatmuslepants

iTrader: (3)

LE is Lloyd Elliot, LE2 is his stage 2 I guess you'd call it heads. http://elliottsportworks.com

AI is Advanced Induction. http://www.advancedinduction.com/LTX/AiLTxMain.php

Both are very well versed in LT1 engines, AI used CNC porting and normally is about 10hp over LE, but more expensive, and Lloyd does all his porting by hand. Lloyd is commended a lot for his excellent customer service. You'll find these 2 are widely used on this and other forums.

tbird31

iTrader: (22)

The 503 cam is a fantastic cam. I had it in my car when it was my daily, before it became the garage queen it is. All the guys above have excellent suggestions, my only addition was try your best not to get caught up in the number game. If you stick with the 503 choice, and get a set of AI ported heads that car will put down 380-400 no problem. (Nothing against Lloyd, I just have more experience with Phil at AI.) My car 503 cam only made 355/350. The low end torque made the car a blast to drive, almost felt faster then my car does now at 422/396.

Also, I'd suggest keeping the 3.73s as well. I liked the 4.10s I had but personally I do a decent amount of highway cruising and just like the fact that 3.73s keep the rpms a touch lower.

bowtienut

iTrader: (1)

If you already have 3.42's, it's kind of frivolous to make the tiny change to 3.73's.
4.10's are ideally suited to the T56 ratios, including daily driving and interstate cruising. Fuel mileage will not suffer.
Race-oriented setups and heavy cruisers actually prefer 4.56's.

1997Z28

If you don't mind me asking what all have you don't to your car to get it into the 422hp range. And will the 373 gears hold the stock rear end without breaking anything?
Someone said to go with 410s but I don't want to lose gas mileage, and still be able to take road trips (if possible).

1997Z28

I'm not to sure about the gears I bought the car completely stock so I don't know what it came with. So your saying with 4.10 gears I won't lose fuel mileage? Heard the rpms will be higher in 6th gear on the highway. But I'm not sure still learning

bowtienut

iTrader: (1)

Your 1997 has the .50 overdrive 6th gear, taller than the earlier T56 trans. In fact all gears except 4th (1:1) in your trans are taller than in the earlier one.
6th gear in yours is nearly useless with stock rearend gearing.
With 4.10's and 26" tires, you'll be spinning 1850 rpm at 70 mph.
If your priority is saving that 0.5 mpg versus better overall performance, then just leave the 3.42's in it.
We just swapped from 3.08 gearing to 3.73 gearing in my son's auto, and observed less than 0.5 mpg change. His rpm at 70 mph is 2350.

StealthFormula

iTrader: (35)

I agree with the above.

The cc503 is a fantastic cam (use to have one) but if you're going to have the heads ported it's really a no brainer to have your head porter spec you a matching custom cam. The cost difference is negligible in the grand scheme of things.

I'd also suggest 4.10's. I have the MN12 tranny in my Z06 with stock factory 3.42 gears which is similar to a MN6 tranny (what you have) with 3.90 gears. I couldn't imagine having any taller gears than that, in fact shorter would be nice so I truly believe 4.10's are the hot ticket. 3.73's or even a 3.90's would still be a step in the right direction but keep in mind your cam choice can and will dictate the minimal amount of gear you will need and 4.10's will cover you pretty much no matter what, not saying 3.73's won't tho too because they very well may.

Ruken

iTrader: (1)

I was just going to jump in and say, the McBride Motorsports Comp TA has 4:10's in it. I wouldn't say its a daily driver but it does see the street once or twice a week and does just fine on the street. My current mod set up, Tune should be here the first week of Sep, then shes going on the dyno shortly after that.

Mods

-Pace Setter Long Tube Ceramic Coated Race Headers and Off Road Y-Pipe
-SLP 2OTL Resonator dumped before axle
-EGR and AIR Pump Delete
-Walbro 255lph in tank fuel pump
-Denny's Nitrous Ready Driveshaft
-Moser 12 bolt rear end with larger 33 spline axles
-Eaton Detroit Truetrac
-Upgraded performance cover with main cap studs
-4.10 gears, and a 1350 yoke
-58mm TB -P&P Intake Mani
-CC503 Cam
-CC Beehive Springs
-Lightly worked heads
-MSD Opti
-MSD Coil
-Taylor Wires


Suspension Mods
-BMR Springs
-BMR Panhard Rod, Chrome Moly, Adj
-BMR Rear Control Arms
-BMR Torque Arm Relocation Crossmember, T56

I used to have a full spool but tires are not cheap and I got tired of explaining to people that there was in fact nothing wrong with my car at slow turning speed. People just dont understand physics I guess. I would start talking about wheel speed while turning and tire scrub and they would just look at me like a deer in headlights

Ty McBride
Team Leader/Owner
McBride Motorsports


Edit: Next mod down the road will be a 24X Ignition System
Edit 2: By the way, my car cruises just fine at Highway speeds. 55K original miles and when I drove it from MT to CO last summer I got 23MPG at and average of 75MPH. (Before Light Head Work and CAM)

tbird31

iTrader: (22)

My setup is just a cleaned up forged 355ci bottom end, ported stock casting heads, big valves etc, ported intake, 231/239 570/585 on a 110LSA cam, and a 58mm throttle body. Supporting fuel and valvetrain along with LTs, ORY, and GMMG catback. I've also got the EFI 24x swap, and an LS1 lid.

Obviously I'm against the grain in here when I say I like 3.73s better. I guess I just didn't like the car sitting at 2200-2300rpm on the interstate, which I do frequent. With 3.73s it sits under 2K and just cruises. Also, I enjoyed actually being able to smack it in 2nd gear and not have to pedal it 90% of the time.

However, as everyone will agree the stock 10 bolt isn't the strongest. Therefore anything over stock power, shoot even at stock power levels, you run the risk of snapping it if you beat on it too much. As far as gas mileage goes, as long as you have stock power, the rear gear isn't going to affect it much. Once you mod, especially camming it, that all goes out the window. Having a competent tuner makes all the difference in the world though. I've built 900hp cars that still get 15-17mpg cruising around town and mid 20s on the interstate.

bowtienut

iTrader: (1)

My own recipe for 425hp/386tq SAE through an A4:
Stock rebuilt bottom, stock rotating assembly, AI 200cc ported LT1 heads, AI 228/234/108 .613" HR cam, stock (unported) LT1 manifold, LT headers.

static low 92

iTrader: (2)

So, im not trying to muddy up the OP original post. But hopefully this will be beneficial to him as well.

But I'm new to LT world, and I got into a nicely modded motor. But still has a stock TB, wondered if it is leaving some on the table and worth the $350-400 to do an aftermarket.

Spec:
Rebuilt Short block, .030 over, I assume stock compression pistons, Edelbrock RPM CNC heads, Crane powermax cam (Lift 479/518 with 1.5 arms. 210/224), Crane 1.6 rockers, Edelbrock airgap intake, Midlength headers, MSD opti/coil/wires. EGR delete

Motor is in a 65 Malibu wagon I think around 3500 lbs. Went consistent 13.5X's 1.9 60' with 4l60e and 3.27 stock open diff rear


Only change I was considering is TB. Worth a change or no?

BALLSS

static..

you should see some power gain from a larger TB...but you would see bigger 1/4 mi with 3:73 gear swap

TB or gear swap, you will need to program PCM for either mod

static low 92

iTrader: (2)

I have heard several people tell me 3.73 also.

Not sure I want to make that move. This car is used ALOT, and my powertour hopefully longhauler next year. I have a 12 bolt in garage intended to be built. So I have options for selecting gears.

Any ideas on what a TB may be worth hp wise? I can't imagine much.

StealthFormula

iTrader: (35)

I might suggest you don't do 3.73's then. As suggested above I agree they are the gear to have in an automatic with performance in mind. I have 3.73's with my auto and it's too much for my liking on the highway. Perfect for everything else IMO butif you plan on using the car a lot and spending time on the highway etc I'd personally keep what you have or to go to a 3.42 at the most.

BALLSS

If the larger TB does give any HP gain with your mods it would only be a few HP if any. Larger TB's do better with heads & cam builds. IMHO a bored stock TB to 52 preferable to any aftermarket TB if you do decide to do it. IMHO given your current mods the larger TB won't hurt anything in terms of performance...just really not give you anything and considering the cost of the TB + $ to reprogram PCM for it (damage to automatic will soon follow if not) I don't think it is worth $ vs performance gain with your set up.

yes 3:73 with a A4 will be better suited for the 1/4 mi and make the car feel "light" and get off the line quicker on the street. Will RPM's be higher at FWY speeds, absolutely. And with that said when I did have a A4 I went from 3:42 to 3:73 and hated them on the Fwy for that reason. I felt the 3:42's were the best "all around" gear for the A4