Im running the slp LM and Y combo, im thinking of adding shorties because I cant go with LT's. Will shorty headers increase sound volume and performance..?

 

Dont go shorties. Go with Mac midlengths I am pretty sure they are emissions legal and will add some horsepower. Do a search but I think shorties are not to popular. The headers also give you better plug access.
Mac midlenghts are the most popular header on here except when it comes to longtubes.

 

well unfortunetely any header is ilegal except the shorties, cause moving the cats from their position is ilegal, even if its one inch, its still breaking the law, although even longtubes will still pass. There are some shops that will pass you and turn a blind eye, but thats kind of a pain to go through. Shorties on LS1 01-02 are supposed to flow abou equal, so your not going to gain much, maybe ten horses. The price of shorties makes it not worthwhile. I plan on using the ilegal mid lenght mids, because you can install them from the top, and also provide great ground clearance, and don't stick out under the car like longtubes, so you have a better chance of passing, and if you must install your stock manifolds its not as hard as longtubes. THe mids are pretty good powerwise, i've seen some peak numbers around 20 rwhp

 

Yes moving the cats is illegal but when you go to do the emissoins testing do you think the person doing the testing is going to know that the cat was moved or not. As long as it is still there you will pass.

 

Mac mids for lt1's dont move your cats, but im not sure about ls1's.

 

To only style he can run since letmeburnu is from california is a shorty header that will only have a CARB# attach. As for the sound, yes it will increase. I had JBA/SLP LM, then switch into a dynomax setup.

Edit: I just notice you have a LS1. LT1 sound totaly diffrent from a LS1, so I wouldnt know to much then from the sound inrease.

 

Damn........mac mid sound tempting but then again i do live in ca so emissions will be a bi#ch. will mac mids go with my slp y-pipe? will it also require 02 sims..?

 

When I was searching for a car out in Cali, I found one wiht longtubes, and hte guy said "ah its no problem i've found a few shops that will pass me" Don't know if it was true or not, but thats what he said. I also talked to a shop out there that said "yeah we install longtubes on these cars all week every week, but I don't know if they pull them off to pass" So aparently people are doing it. One dealership I went to was selling an 01 ram air that had an off road Y on it, and obviously no cats. I told the guy who sent out a mechanic and confirmed it and said, well we will install some before selling the car to you. I know they sold the car, but don't know if they did or not. When they do testing out there (cali) do they open up the hood and check everything out, or do they just put the car on the machine and test?

I think your aftermarket Y could be used with the macs, of course they will still need to be shortened and have some reducers welded on, but thats not to hard to have done. Many guys don't like the ball and socket connection on the macs, cause it restrics the flow a little, so they have them cut and put the regular reducers on. You'll have to move the cats back farther as well, so you'll need to either get sims or extenders. Personally I'd get extenders, as the rear O2's are only there to test the cats, so the sims won';t ever need replacing, but the 02s will, and i doubt the inspector will go under the car to see if you have them. IF you have your old cats you could just have a custom Y made with the cats put in. Then you could run around to different shops andsee if one will pass you, and if not you could pull the headers and install the stock stuff. I really wish they would change the rules, I mean if the car still passes what is the big deal?

 

If you are only going to do shorty headers leave the stock manifolds on and save your money! They flow about the same which some have posted here already. You could do cutouts after the cats if you wanted??