Best combo for high 11's 2004 GTO
 

Hey guys I am new to the LS field. I have a 2004 gto t56 car, and its stone stock and 98xxx miles. Its my daily driver and I managed to squeeze 13.90's out of it stone stock, but I want to go high 11's for now. What is the best combination to achieve this goal?

I was thinking a set of heads, and a good custom cam. Full exhaust and obviously some good tires. I see the z28's running 11's with similar mods, I know my car does weigh 3700 pounds but I will do some weight reduction. So if i do full bolt on's and a good solid HC setup and the car weighing about 3500 could i see my 11's?

Any advice would be greatly appreciated!

Yeah it can happen with the right setup pretty easily. 3500lbs is about as light as our cars can get without going crazy haha If I were you I would start beefing up the drivetrain first.

The manual trans might make that difficult in a heavier car.

Power wise as a rough estimate plan on needing around 200rwhp more than you make now unless you can drop a good bit of weight.

Better make sure your clutch, driveshaft, and half shafts are ready to see the abuse too.

I don't see an 11.9 being an issue at full weight with a decent HCI. Just mount some MT's on the stock rims and you should get a decent 60ft which should do the trick

Thanks for the replies guys. I was thinking of going automatic with the car anyway. I too feel the weight could be an issue with the stick, but i just don't see the car needing almost 500whp to crack high 11's. What is the best bang for the buck cylinder head?

I would throw a mid 230's duration cam in it with a set of stock milled 243 heads and get it tuned. Headers/exhaust would help as well as a clutch at that point too.

What about a centrifugal blower, and a cam? what that get me my goals?

A friend here had an ls2 gto with a stalled auto and an overdriven magnacharger, x pipe, typical weight reduction, and that was getting close (I think traction limited). Eventually just added a small nitrous shot on top of that with some better tire and ran some 11.20s IIRC.

If you think about a common street fbody running low 13s stock and adding heads, cam, and bolt ons to run mid-high 11s in a manual trans car then plan those same mods on a car that's running high 13s what I said makes a little more sense. Not saying it's impossible or even unprobable...but I like to err on the side of caution so I'm not disappointed.

The more weight you can drop the better and the less power you will need obviously.

Here's what I'd do:

BTR Hand-Finished TFS As-Cast 220 heads, FTI StreetSwepper-HT 228/232 111 Cam, ARH 1-7/8" Headers, Monster Stage 2 clutch, 3.91 gears, MT ET Street Radial 2s, and a 150 shot of nitrous.

I'd buy DSS parts for the rear end before you even think about adding power to a GTO. I've broken many stock rear end parts in many 04-06 GTO's with completely stock power just trying to launch.

The 5th gen Camaro SS rear is weak...the 04-06 GTO rear is even worse.

Suspension and weight are serious problems for a Gto trying to drag race.
Thunderstruck was talking about my Gto. Even with a decent tire and enough power there are lots of things working against you. Unless you've removed some stuff already it doesn't weigh 3700 with you and fuel in it.
If you do get it to hook decently there's a good chance it breaks a half shaft, rear end, or stock driveshaft.
With the irs and weak stock springs it will squat way too hard, and then unload a little past the 60' mark, and either start wheel hopping badly or haze the tires again.
Drag bags are a good bandaid but the real problem is the stock spring/shock combo.

I've made a bunch of passes in my car, and ill make a bunch more, but you can't expect it to react the same as an fbody.
My car trapped 127 but still only ran an 11.2, an fbody with similar trap speed and a good 60 would be deep into the 10s

It really sucks how much money we have to put into these cars just on suspension and drivetrain to get it down the track.

I don't know anything about the GTO rearend but with the M6 it makes sense you need to address it as others are saying.

That said if I can make a heads/cam LT1 Caprice run 11s you should be able to make a heads/cam GTO run 11s even with a harder time making it 60ft.

I wouldn't look at boost or nitrous to get there.

I would always look to nitrous to hit a number. It's much more cost effective than anything else.

Think about this: a 150 shot of nitrous is safe on these motors. It's also more than any heads/cam package will add to your car. And it adds a lot more torque than those packages so it's typically faster given all other variables are the same. It also doesn't impact drivability or anything. But combine H/C/I+nitrous and yeah... that's upwards of 300rwhp added to the car.

Swap to an automatic. With the IRS launching a M6 GTO is very difficult. It is a great GT car and a middling drag car.

Build from the back to the front man. Also do suspension as well before you do engine work.

Yep. Realized that years ago. Nice DD HWY car.

Ok I love the head and cam options you guys listed, and have been looking into all of them. All seem to be a great choice, and I have some other questions. The half shafts from what I read seem to be the weak point of the IRS. I also found guys running the 6.0 half shafts as a cheap upgrade.

Also call me search challenged, but i looked and looked and heard about these drag bags but CAN'T find them on any of the big performance parts dealers sites... Jegs or Summit racing.

All I can say is I was actually happy that my friends full bolt on 2v gt with 4:10's could hold me at the top end, and im stock :)

As far as the auto goes I have a access to a nicely used TH400 with, full manual valvebody and was behind a 6.0 for cheap. What would I need to delete/program from the computer to make this work. I heard I could use my M6 cross member with modifications to get it to work. I would love to see what I could run with a TH400 and bolt on's. Let me know what you guys think and thanks for the advice!

I have a used set of drag bags if you are interested.

Id be pretty disappointed if I didn't walk a bolt on 2v

Might need more than heads/cam...haha