roger1984

Hello, i have a 2002 Trans Am WS6 Automatic Stock except for slp air lid.

i would like to have 400RWHP in it, what would you recommend me upgrading?

i am not interested in NOS.

Regards, Roger

conan

iTrader: (5)

Cam, Stall, Headers, Y pipe, Catback... Tune

HCI2000SS

iTrader: (2)

Cam may or may not get you there depending on the dyno. Heads and cam together will

roger1984

Thanks for the replies! what would be the approximate cost of changing cam and heads including having a professional doing it for me?

by heads you mean headers right?

Regards, Roger

HCI2000SS

iTrader: (2)

No by heads I mean changing the actual heads lol. That along with a cam and full exhaust. For a decent set of new heads with cam, labor and tune you probably looking at around 3-4k or so

autogeek23

iTrader: (13)

Bingo!!!

a good y pipe too. TSP is affordable and a great design.

being an auto it will be more difficult to hit 400whp on a dyno.

there is a local to me shop that has a LS cam upgrade package that includes the supporting mods that has many LS1's hitting 401whp on their mustang dyno

LS6 Intake
600 lift cam package
Headers and ORY
Dyno Tuned.

if you are a DIY guy then you will save a lot of money.

Furious1

iTrader: (1)

I hit 390 RWHP with the mods in my sig. A set of heads would easily put it over the 400. Do not forget you will need supporting mods with the cam & stall (springs, lifters, oil pump, transmission fluid cooler).

99Bluz28

iTrader: (35)

First the easy part. You'll also want a set of good 1-7/8" headers and a matching Y-pipe, along with a cat-back exhaust. Keep in mind you exhaust will be noticeably louder with H/C setup, so you might want to get a cat-back that's not excessively loud. Then you'll need to figure out what you want and don't want from a cam swap. Once you know the cam you want you'll need a Higher stall TC (3200-3600), the stall rpm needed for optimum performance an drivability will depend on the cam you plan to go with. Most LS1Tech sponsors will let you know what size stall rpm they recommend for their various cams. Heads will help you meet or likely exceed you goals, but they might not be necessary to just reach you goals. A set of CNC ported factor gm heads will get you there. Last but not least, supporting modification will easily add $1K to $1.5K to the cost. As far as install cost I don't have a clue, I do it all myself when ever possible except for the tune.

98Z28NMB21

MAF, Throttle Body, Headers, if your in a free state delete your cats and go with a Xpipe. you'll be glad you did once you start dicking with a heads and cam set up. I'm not gonna get into a long strung out discussion over cams because everyone and their brother has a different idea about em but I'm running a H/C/I set up in my 98 M6 and the cam is a G5X3 before I got my heads I was just a cam only with this cam and LOVE IT!! but it all depends on what you want, A dyno queen, or a fast street strip car? what?

ULTIMATEORANGESS

iTrader: (4)

400rwhp through an auto with a killer cam will be tough even on a dynojet.


take into consideration street ability not just numbers.

gMAG

iTrader: (1)

Get a midrange cam, headers, and port your own heads.

goldcar

This^^^ Is decent information BUT a upgraded MAF, and Throttle body are not really mods to do even once your at 400whp they aren't exactly worth it. Just thought id put that out there.

goldcar

Oh and for the OP's question... Well you'll need to have a lot of money to make 400whp RELIABLY but with a decent head/cam package it can be achieved relatively easy.

These are parts that will hender it being a reliable 400rwhp car

Factory rear end (Usually wont hold after a few good lanches)
Transmission (Usually starts slipping bad)

And what others mean by supporting mods are basically mods that get more air in/out faster and more efficiently.

projectX

iTrader: (51)

224 or 228 cam, 3200/3600 stall, ls2/6 heads, headers and a tune. Done!

30th t/a

iTrader: (51)

I agree with this guy. Make sure you mill the heads to get the compression up. You'll get 400rwhp.

Might has well figure in a built transmission too. 4L60e's are not very strong.

roger1984

Thanks for all the answers guys! i really appreciate your help!

i am now concerned that my car wont hold for that kind of RWHP as goldcar mentioned...

i have already taken some precautions for the 4L60E transmission by putting on a big *** Haydens Transmission cooler..i dont know if that it enough though...

I am interested in getting a fast street car, not just dyno numbers. But its also very important that the can take the kind of horsepower i am putting in.


How much rwhp can the factory rear end and automatic transmission take?

By the way is it possible to keep the stock MPG even after changing cam and heads? (under normal driving conditions of course)

Mavn

iTrader: (3)

You need a trans go hd2 at minimum..

Furious1

iTrader: (1)

With an auto I wouldnt be as concerned about shredding your rear end unless you are running slicks.

30th t/a

iTrader: (51)

The stock 4L60e starts to go to **** around 400rwhp. It might last a little while but the more you jump on it, the quicker it will start to slip.

Hooking up is what breaks the rearend, not rwhp. I ran 603rwhp/600rwtq with my stock 10 bolt with BFG drag radials and it was fine but I wasn't out pulling crazy hole shots at every stop light with slicks. Launching with a Auto trans doesn't give that sudden jolt of torque to the rearend like dumping the clutch with a manual does. That's why stock 10 bolts seem to last longer with a A4 trans. If your going to be on the street more, Id leave the 10 bolt for now. If you plan on going to the track every weekend, leave the stock rear in for now, but plan on getting a 12 bolt or 9" rearend.

Gas mileage will go down but should remain respectable for a 400rwhp car.

projectX

iTrader: (51)

My trans broke right after I put headers on!! lol good old' 3/4 clutches. All I did for my rear was 3.73 gears and a refresh kit. Tracked the car only twice a year but dead hooked on mt et streets no issues. As the guy above stated dead hooking and I'd like to add wheel hop kills these rears.