1976 L48 Mod Suggestions

[majortom75]

By the way, I ordered the dual exhaust kit from Mid-America today. I'm looking to get the Flowmaster Stainless Delta 40 Series mufflers. Can't wait. The stock exhaust sounds horrible. Anyone have experience with this muffler?

 

[mmvette80]

Ok, cool. So when my car is 25 yrs old it will be exempt from emissions, BUT they will look under the car to make sure of a cat?

When 2005 comes around im gona have a stiff drink! :bar

 

[offshore]

The catalytic converters are Federal law. The reason I do not have to pass emmissions is because the car is 25+ yrs old. The info in on NY states DMV web site. The url is :www.nydmv.state.ny.us/

Unfortunately, you will have to wait until you eclipse the 25 year mark for NY.

you don't get it your car might not have to pass state emission test but you still need cats .your car came with them! what a lot of states are going to do is road side emmission inspections just like truck weigh stations. And It does'nt matter what year your car is. Not only that but your car needs the same clean air to breath that you do! if you use high flow cats you'll prob see a slight increase in hp. all neh marine eng ines have to pass emmissions too. what we have fonnd is cats even our water cooled ones incrase hp. do to the higher int.exhaust temps.

 

[majortom75]

I know. Sorry if I was vague. I plan on going with dual Dynomax high flow cats. The law does say that if the car came with cats, they need to remain on the car.

 

[MaineShark]

I know. Sorry if I was vague. I plan on going with dual Dynomax high flow cats. The law does say that if the car came with cats, they need to remain on the car.

Dual cats are not any more legal than no cats, for a car that originally had a Y-pipe and a single cat. The law doesn't just say "it needs catalytic converter(s) of some sort" - the law requires that all original emissions equipment (or direct replacements) be used. That means Y-pipes, cat, EGR, AIR, etc. etc. etc.

Now, enforcement is pretty lax, so you can probably get away with it, on an older car like these. But I can't see any reason to spend money on two cats, when it won't solve the legal problem, anyway. If you've going to ignore the emissions law, why not just save some money, and go with true duals?

Jo

 

[offshore]

Dual cats are not any more legal than no cats, for a car that originally had a Y-pipe and a single cat. The law doesn't just say "it needs catalytic converter(s) of some sort" - the law requires that all original emissions equipment (or direct replacements) be used. That means Y-pipes, cat, EGR, AIR, etc. etc. etc.

Now, enforcement is pretty lax, so you can probably get away with it, on an older car like these. But I can't see any reason to spend money on two cats, when it won't solve the legal problem, anyway. If you've going to ignore the emissions law, why not just save some money, and go with true duals?

Jo

:argue WHAT IN THE HELL IS YOUR POINT! If a cat is required and you change to dual ex. than you need 2!

 

[MaineShark]

If a cat is required and you change to dual ex. than you need 2!

It's not just "a cat is required." The entire original-type exhaust, with two Y-pipes and one cat, is required. The Federal Clean Air Act requires that the exhaust system remain idential to factory spec. A dual cat setup on a car that originally had one cat, is no more legal than no cats at all. Even replacing that single cat with one that does not meet the oem specs is a violation.

If it came with Y-pipes and a single cat, the only legal setup is Y-pipes and a single cat. That's why all dual-exhaust conversions for the 1975-1982 Sharks say "for off-road use only." If you're going to be violating the Clean Air Act, anyway, you might as well save the money and not invest in a pair of un-needed cats, IMO.

Jo

 

[offshore]

It's not just "a cat is required." The entire original-type exhaust, with two Y-pipes and one cat, is required. The Federal Clean Air Act requires that the exhaust system remain idential to factory spec. A dual cat setup on a car that originally had one cat, is no more legal than no cats at all. Even replacing that single cat with one that does not meet the oem specs is a violation.

If it came with Y-pipes and a single cat, the only legal setup is Y-pipes and a single cat. That's why all dual-exhaust conversions for the 1975-1982 Sharks say "for off-road use only." If you're going to be violating the Clean Air Act, anyway, you might as well save the money and not invest in a pair of un-needed cats, IMO.

Jo

 

[majortom75]

I checked EPA guidelines. Maineshark is correct. Darn EPA. I guess I'll try just the high flow cat. Anyone have any experience with improvements using hi-flo cat and mufflers?

 

[offshore]

I just check the guide lines too Shark is "WRONG" The clean air act of Jan.1 1992 said you could not change any configuration of the eng,ex,elec,ect But ammended it 6/192 to state Liability for any changes to any sys. covered by the caa 1/1/92 shall be the responablity of the owner. (this means if the pre.owner changed something and it doesn't pass your responsible!) now in the ammendment it states that ANY MODIFICATION meeting (CARB) specs. shall be allowed by state and fed. regs. "HORSE POWER CAN BE CLEAN" THERE WORDS NOT MINE. Dual cats are legal! The sick part is I knew this I jut couldn't remember the (carb) law. I had to search the epa web site to tell me somthing I allreadt KNOW I have hundredes of (carb) stickers in my shop but never use them!

 

[majortom75]

offshore,

Can you supply the url on the EPA's web site for this? I can't find it. Thanks.

 

[offshore]

www.epa.gov/complinace it took me an hour to find the wright page. but thats where i started. But you can save yourself the trouble.( thats why I'm so mad at myself) most after market parts come with a carb. sticker & say 50 state legal. I got the stickers 10 years ago so if i made changes to a car i had to cert. the changes were carb. legal and provide the paper work to the owner to prove it. the sticker had to be displayed in the eng. compartment. I think I used 4 of them. In fact now that I think about it any hp. part you buy will say (carb.cert.) 50 satae legal or for( off road use only!) anything that says carb. is roadable! Have fun with your new LEGAL daul cat & header exhayst sys.

 

[MaineShark]

Exactly how many dual cat systems have you seen that are CARB-certified? CARB certifies parts which meet a substantially similar function to the original. A single high-flow cat may have a CARB certification for this application. A conversion kit to use dual cats will not have CARB certification, because it is not substantially similar to the original.

The only way to convert your car to dual cats, and remain legal, would be to submit the modified car for Federal testing, which costs several grand, and there is no guarantee that it would pass.

Also, state laws requiring that original equipment remain in place, may still apply. The EPA can't just "require" states to allow things - any State may enact tighter laws than the Federal standard.

The light at the end of the tunnel, is that enforcement is low, in many areas. In which case, why spend money on two cats?

Joe

 

[LEEJANDZ]

Ganey -- Next is cam, HE268H is a good start for 4 spd. & max. for stock valve springs. Intake has to come off so is a good time to intake.

Is that your recomendation for an automatic as well?

:Silly :Silly :Silly

 

[offshore]

Exactly how many dual cat systems have you seen that are CARB-certified? CARB certifies parts which meet a substantially similar function to the original. A single high-flow cat may have a CARB certification for this application. A conversion kit to use dual cats will not have CARB certification, because it is not substantially similar to the original.

The only way to convert your car to dual cats, and remain legal, would be to submit the modified car for Federal testing, which costs several grand, and there is no guarantee that it would pass.

Also, state laws requiring that original equipment remain in place, may still apply. The EPA can't just "require" states to allow things - any State may enact tighter laws than the Federal standard.

The light at the end of the tunnel, is that enforcement is low, in many areas. In which case, why spend money on two cats?

Joe

corsa & magna flow both make carb cert. dual in dual out c4 exhaust. and thats just 2 co. I you have a problem with the law the epa's tell# is at the web address above!

 

[MaineShark]

We're talking about C3's, here. And I just checked Corsa's site, and they only list a cat-back system for the C4, so they would not be replacing anything about the cat, anyway.

I can't seem to find anything but cat-backs and direct replacements in Magnaflow's catalog, either.

I'm well aware of the law. I've talked to the EPA on several occasions regarding this. They have been quite clear about the requirements of the law, with regards to replacing a single cat with dual cats. Any certified replacement part will be substantially similar to the original. A certified intake manifold, for example, will have EGR passages. A certified exhaust manifold will have AIR fittings. A certified exhause system will have the same number and location of cats. Etc. etc.

Joe

 

[Ganey]

:duh isn't that exactly what I said? except you "do "need the heads to approch 300 hp! Hey whay do I know.:Roll

NO, you said:

good luck on $ 1000 PREFORMER KIT $465.( MANIFOLD,CARB,CAM & LIFTERS) CLY. HEADS $1000. TIMING CHAIN $ 40. PUSHRODS $35. GASKETS $ 55. HEADERS (COATED) $ 225. OIL & FILTER $ 25 ANTI-FREEZE $ 14. TOTAL $ 1854. NOW YOU HAVE TO PUT TOGETHER AND THAT SHOULD GET YOU JUST ABOUT WHERE YOU WANT TO BE.

The cam 2102 that is part of the pkg. you rec. is not enough cam for a 350 CORVETTE. Better than stock L-48, good stock replacement, not rec. for a 350 CORVETTE!

No problem making over 300 HP w/ stock heads.

BTW, Did back you up on the 800 Carter is too much for mild 350.

 

[Ganey]

Is that your recomendation for an automatic as well?

:Silly :Silly :Silly

For a stock L-48 auto./converter/gears w/o rebuild, you would probably be happier w/ 1 step down to HE 260H or XE256. This gives more low rpm HP/TQ to get you off the line & only about 20 less hp at high rpm. This is about 1 step up over the Edel. Performer 2102 cam.

 

[LEEJANDZ]

;help ;help ;help

Ganey -- For a stock L-48 auto./converter/gears w/o rebuild, you would probably be happier w/ 1 step down to HE 260H or XE256. This gives more low rpm HP/TQ to get you off the line & only about 20 less hp at high rpm. This is about 1 step up over the Edel. Performer 2102 cam

I have a 79 L-82 with a B&M automatic & true dual exhaust.
I am awaiting arrival of my EDELBROCK 2101 and was considering doing a cam swap at the same time.

What do you think?

;help ;help ;help

 

[Ganey]

LEEJANDZ

HE268H is smog legal & max. for stock valve springs. When you do the heads you could go to 1.6 roller tip (all that's needed) rockers. The XE262 is similiar w/ more ex. duration, another possibility, new valve springs needed.