Hey guys so after buying the huron v2 kit and realizing that I do not want to deal with a 3k fine if I get pulled over for not having cats I am going to sell the setup. So I was wondering if I would be able to get a H/C/I setup that will put me at 400+ whp. My budget is $2500. I already have 80lb injectors and a 255 fuel pump. I was thinking ls6 heads and intake and then a cam package. The only thing is I cannot use long tubes as I do not want to remove my cats.

 

The stock cats will hurt getting to the goal of 400 wheel horse power. The stock cats have around 2 inch inlet diameter which is on the small side to get your horsepower goal. You can have cats with long tube headers just get 3 inch y pipe with high performance low restriction cats.

KOOK's and American Racing both offer that header & y pipe set up. Other vendors like Texas Speed & Performance probably do too. There used to 3 inch high flo cats that would fit inside the y pipe, Jet-Hot offered them with their 3 inch y pipe for Hooker long tube headers. I'm not sure if those are still offered or if that type of cat would address you cat concern.

With long tube headers, LS6 intake, good size aggressive cam and tune many members on this board have made 400+ at the wheels.

Keeping the stock cats, would mean keeping the stock exhaust manifolds or shorty headers. While a good shorty header (especially one with 1 3/4 primary tubes) would flow better than the 4th gen fbody stock manifolds those stock cats will still choke the exhaust. If going with shorty headers and keeping the stock cat locations, I would still upgrade to a high flow high performance cat to improve exhaust flow and chace a better chance at hitting 400 wheel hp.

If you have to keep the stock cats & manifolds, I would get AI or TEA to port those LS6 heads. AI or TEA can probably suggest a suitable dual pattern cam with 10 to 16 degrees more exhaust duration to work around the hamstrung stock exhuast. Maybe something like a 224/236 etc.

I have a pair of extrude hone ported cast iron 4th Gen exhaust manifolds if your interested. They have bigger exhaust ports than they did stock. I'm not sure how much hp the porting is worth. I've heard zero hp and i've heard 3-7hp with supporting mods.

The stock fuel system in good working order (clean fuel filter, good stock injectors) is usually good to about 450 wheel horsepower.

Good ​​​​​luck with the build.

 

I live in california though so the cats would need to be in the same location as the old being moved only 3 in either direction. So would the carted y pipe still work? The stock cats are right behind the manifold so if it on the y pipe I don't think that would be legal in california anymore

 

Long tubes with catted y pipe would move the cats more than 3 inches.

Sounds like CARB legal shortie headers and new hi flow cats will be as good as it gets.

JBA has a nice selection of CARB legal shorty headers and hi flow cats & 2.5 inch mid/y pipes. I would check out their products. Ideally, you will want a 1 3/4 primary shorty header for you goals. JBA is located in California so they should have a good idea of what works with in the restrictions.

 

So I went on JBA's website and they only have headers in 1 5/8. Didn't see anything 1 3/4. Will the 1 5/8 do the job? So I have been chatting with Gary at Texas Speed and he told me to go with stage 2.5 5.3 heads and cam package to hit my goals. What do you think about that? Would this be better than porting a 243? He recommended a torquer v2 cam. I don't want a cam that's too aggressive because I don't want to lose to much power down low. This is a daily driver so I want power throughout the powerband band. If the high flow cats are smog legal here in California then I will go ahead and get those as well. Also I am not worried if the headers themselves are not smog legal as thats just a fix it ticket. its more I do not want to move the cat or remove them as that's a federal offense and a $3000 fine.

 

Your right, the 1 3/4 JBA shorties are for the Gen 5 camaro, C5 vette & 2014+ SS, none for the 4th Gen fcar.

Is your cam a six speed or an automatic? If auto, what stall conveter or stock?

What rear gear ratio?

Other mods to the car?

The more info the forum has on your car the better suggestions and comments etc.

TS&P has an excellent reputation and quality product.

For $1500 I think you can get some top quality ported 243's.

I would also talk to Lingenfelter, they have extensive experience with making power with in the CARB restrictions. Lingenfelter also has a very nice CNC'd 243 offering. I recently picked up a pair of their CNC'd 243's and was impressed.

TEA and AI are also excellent with cylinder heads and suggest contacting them as well as BTR.

 

SSV8, this maybe an interesting read. Corvette with shorty headers & PRC 5.3's

http://www.corvetteforum.com/forums/...3-heads-2.html

 

You sure you can't hide a turbo in the rear? Make the plumbing real subtle to look factory, hide with some factory plastic looking cowl to cover the tube and turbine. I've seen it done but not on a car with a cat though. just an idea, probably useless and expensive, but with enough time and money anything can be accomplished on a vehicle you can dream of.

 

Its a 6 speed. For the rear gear I will have to check out the RPO tag and get back to you. Car is bone stock as of right now. Was going turbo, but scratched that idea because of cats. All the 243's I see are way past 1500 thats why I was looking at the 5.3's. Gary was telling me with cam they should get really close to 400 on stock manifolds with ls6 intake. I will check out lingenfelter. TEA's website wont load to well, but they have their stage 2 for $1500 is that the one you were talking about? its the only one in my budget on that website. Can't really specs because of the website. The turbo doesn't need to be hidden. I can get the car smogged with the turbo, but I do not want to get pulled over for not having cats. It is a pretty big fine. I'll check that link out right now thanks!

 

AI seem to be $2500+ on their heads which is past the budget. You said I can get some 243 ported for $1500 which vendors sell them for around that price? I contacted AI to see what they have to say. If lifted07sierra made 370/373 without cams I should deff be in 400 territory with cams. Again thanks for the help. The BTR heads seem pretty cheap compared to the rest. I contacted BTR so lets see what they have to say. So TEA website worked and I saw there stage 2 around $1500. If I can find some used 243s it would put right around 2k plus. Trying to see which of these would be better to get now. I've seen a post by bluebirdls1 where he had stock manifolds and made 430 rwhp on a 124r cam. Also read the 5.3 doesn't have much torque under 3k. Is that true? I like torque down low for a lot of in town driving. One of the reasons I love my car right now

 

SSV8 sent you a PM

My 99 T/A has a very old set of TEA Stage 2 5.3's from back in 2002. They drive very well idle to 6800 rpm. The ports are improved but NOT hogged out. The air speed stays up so they ar responsive. Ask any prospective vendor about intake port size smaller port tends to drive nicer at low rpm. Most well done factory LS heads under 235 cc port volume are usually pretty good drive wise. If the factory casting has been ported to 250 cc port or bigger there could be some lazy response.

I​​​​​'m not sure what approximate spec cam would work best with shorty headers and cats, im going to guess a good split duration like 227/235 etc. BTR aka Brian Tooley, Patrick G, Predator Z, Ed Curtis, Martin Smallwood all have excellent reputations for cam selection and custom cams matched to your application. Spending the tim on reseach and getting information will help making the best decision for your cars's set up.

LPE's GT 1-1, with 215/231 duration @ .050 lift - .631/.644 lift with 1.7 118.0 CL would probably work very nice if you ever decide to think about forced induction again. With a set of matched great flowing heads i woild think this cam would do pretty darn well. Patrick G had a 215 cam that made 400ish hp but i cant recall the spec's

My 5.3's would have made more power with more work on the exhaust side per my two friends that did the install, both SAM grads with professional race engine building experience. If looking at any cnc'd 5.3 head I would ask if the exhaust side can be improve with a little hand finishing or diffenent valve etc.

All 4th gen six speed cars are more fun with gears! This is even more true if a 224+ size cam is being used. Even if you dont do heads and cam, 3.73 or 4.10 gears are one of the most fun best mods for these six speed cars.

 

I emailed a couple of vendors and I am waiting for a response. The 5.3's and stage 2 ls6 from Texas Speed both seem good to me so I am trying find out which one I should go with. They are both around the same price. I will look into the cam you mentioned as a I do plan to go FI in the future, but this time it'll be a remote mount setup so I can keep the cats. So far only Texas Speed has gotten back to me and he recommended the torquer v2 with the 5.3's. I kind of want to buy both heads and cams from one vendor so I get a better price unless I can get the heads you pm'd me about.

 

Just a slight correction...LPE GT 1-1 is a 229 242 .631 .631 114. The GT11 is the 215 231 .631 .644 118.

 

Buy used 243 heads say for around $400 and send them to AI. they will port them for $1000 plus the price of what ever springs you want. So in total you will be around $1700 in total. Tea ported 243 stage 1 heads with the cost of your 243's being $400 will cost around $1800 total. Stage 2 will cost $220 more. You can get Trickflow's 220 as cast from BTR with some milding porting ready to go in the range of $2100 which are a better head than the 243's.

If you don't already have the 243 heads or get a great deal on a pair i would go with the BTR trickflow heads.

Or you could send your stock heads to AI and it will cost you around $1300 and only lose about 10- 15 hp compared to ported 243 heads.

 

Lol I think ppl are forgetting the part that you said your budget is 2500....


Ill be honest you not gonna get passed 400 with that budget and your restrictions.

 

​​​​​​​when you say cast heads are you talking cast iron heads? Like truck manifolds? I'm trying to get as close to 400 whp as I can with my budget and then I'll get supporting mods to go with it down the road. I have to stick with shorties though which I know are going to hold me back, but like I said I live in cali and just don't want to deal with getting pulled over on a road trip and having the car impounded.

 

Not sure where i said cast heads but all the heads i was talking about are aluminum. The only cast iron Ls heads that i know of are the 1999-2001 LQ4 6.0 which no one uses.

https://ls1tech.com/forums/dynamomet...ds-please.html

 

gagliano7, I think SSV8 got confused when you mentioned the Trickflow 220 as cast heads. I think he thought you were say that they were a cast iron head.

SSV8 the Trickflow 220 as cast heads are a cast aluminum copy of the cnc ported Trickflow 215 heads. The 220s are a good bit cheaper and almost as good. For the money it is hard to beat the Trickflow 220 as cast heads. See my sig below.