Ok its time to start building my new motor. heres the plans im getting a 6.0l iron truck block from a friend that spun a bearing. Thinking 408 with L92 heads, cam i want somthing i can get to pass smog ideas please, I was thinking fast setup and trying to take the name off and paint it black but like I said I want to try and keep it as close to smog legal but it may come to that. Also would like to maybe hit with a 200 hit of spray. So whats my options and what kind of power am i looking at making smog legal within reason.

 

a 408 wont pass. and if you did want to build a 408 and put in a cam that passed smog it would not run very well cuz the duration on the cam would be way too low 4 a motor like that to make power. and technically a lq4 would not be smog legal in cali because its a motor swap other than an ls1. you would have to take it to a ref to have it barred.

 

The iron block will be a giveaway if the smog tech is sharp... how good can you paint it to look like aluminum...?

If you can make the FAST look dead stock then just maybe he won't notice that.

From my researching into this:
to pass the sniffer the cam has to have some amount of negative overlap (underlap)... at least 4° of underlap... this would get you low-mid range and start dropping off up the high.

408ci displacement might produce too high level of hydrocarbon's... or maybe with new cats and NBO2 you might be able to slide in under... the sniffer is looking at HC, CO, and NOx, functioning front NBO2's and cats should get all 3 levels sufficiently low to pass.

Spray would have to be completely stealth/hidden, no wires/hoses showing at all.

You will have to have EGR, AIR, EVAP, front NBO2, rear NBO2, and cats all present (with stock exhaust manifolds)... the tech will look for all of these.

No check engine light, and only 1 monitor not ready (maybe 2 prior to 2001).

 

would he even beable to tell its not a ls1 besides a small cam? or am i just all wrong. i really dont want to do a motor swap ever time i got to smog.now we are talking. I may even have a tech that may over look a few things.

 

Do you guys think it would be easier to just pull my stock ls1 and build it. but if I go this way what setup to still keep it under the radar im not set on the 6.0l block and l92 heads.

 

Being from CA, I have a ton of experience with smog crap and trying to get around them. Basically what the others said is true. If the smog tech is really good, he will be able to spot that the intake and block are not stock. However, I know that they're are techs out there who don't know their *** from their face, and wouldn't be able to tell that the engine isn't stock. Or you can go to a test only smog place, where you don't pay if you fail the test.

Your best bet is to build up a stock LS1 block with a stroker crank and some nice ported heads. A 408 would easily pass the sniffer with a small enough cam. If you're mechanically handy, you can swap out cams in a day's worth of work and be good to go.

Personally, I would give the 408 + FAST a try. I'm positive you can find a smog tech (especially in Stockton) that has virtually zero experience with LS cars.

 

I believe i have a tech that will over look the visual as long as i get it to pass the sniffer im good. from what i have read im thinking I really might pull this off. So its on 408 l92 heads with a fast setup, stealth is the plans here so im still going to paint the intake and try to make the TB look stock as possiable. nitrous plate is even good as long as I dont have the lines hooked up I have my cam guy setting up a cam now, will post specs. we are going to walking on a fine line here.

 

we need a sticky for people dealing with emissions,cams,intake,exhaust.

 

I wonder if anyone knows someone that has actually passed a 'legitimate' sniffer test with a 408. I have a hard time believing you could run a cam small enough to pass the sniffer and still make the motor run decent. I haven't heard of anyone passing with a 408 before, but that doesn't mean that no one has.

 

It's not so much the cam being small as it is a sufficient lack of overlap.

 

predator-Z could spec you a cam.he talked about negative overlap in another smog thread.he mentioned some off the shelf cams that mite pass emissions. why not use a stock gm ls3 intake?I would think they are cheaper,and there are plenty of them out there.

 

the only cams you can run must have no more than -4 overlap. and a cam like that does not have alot of duration. thats y im gonna run the 224r. im building an iron 370 11.1.1 motor cuz the cam is not too too small for the ci but i would think that a 408 would not run to well with that small of a cam. its not all about ci but more about your setup. for the price of building a 408 (machine work and parts) y not just buy a smog legal pro charger or turbo kit? if i had the money i would do that for sure.

 

If I was doing this, I would get whatever cam you want for the motor for big power, and then a stock cam for smog. If you put a smoggable cam in a 408 you aren't going to yield much in the way of performance. Swapping cams isn't much work, considering you would only have to do it every two years tops. A two-piece timing cover would be a WISE investment, that way you won't have to pull the balancer and get a new bolt every time. Those are just my thoughts.

FYI, you probably don't want to post about your "connections." You never know who is watching

 

ya this is going to be what happens. im going to have a big power cam cut then I will keep one to smog and just do swaps. connection what connection

 

Exactly, small as in not much overlap, or more precisely negative overlap. I think you could probably have a bigger cam in a 408 than a 346 and still pass smog, but then again I haven't seen too many examples of a 408 that can pass the sniffer.

 

Im not 100% sure, but ive heard that theres some counties in cali that only require smog whenever you sell the car. Theres a list in the DMV website that show which counties are smog exempt. So basically you only get your car smogged once when you buy the car, and then youre free from smog until you decide to sell it.

 

Yes, smog varies not just county to county, but in different ZIP codes. Somewhere online you can see what ZIP code has what smog requirements. There is "enhanced" where they put the car on rollers and do a couple tests under load. Regular smog is where they just rev it up in neutral. Some ZIP's don't require smog testing like you mentioned. Those ZIPs are usually very rural areas. I've managed to find a few

 

I'll be back in Cali this May. I kind of don't want to buy another LS car because of smog. I'm trying to find out if my old ported 90 combo is smog legal. I wish I could just only pass the sniffer and not have them care about the visual. It's a shame to hide a good looking nitrous kit too.