Hi everyone, I've got an 87 Firebird with a 350 swapped in, and a carb sitting on top.

Sorry in advance for the long post, but I'm really hurting for some help here, and my weeks of searching are turning up dry anymore. Thanks in advance for the help!!

I need to get this car registered in Georgia, which means it has to pass emissions inspection..

Well, it's got some GM cylinder heads on it (can't remember the casting number, but its 72cc combustion chamber, and 1.5 / 1.9 valves in it, as I recall). It's also got an Edelbrock intake manifold WITHOUT EGR, no A.I.R. pump or belt, no CAT, and a schlepped-together exhaust in it (no real Y-pipe, just the left and right banks coming together at a right angle.... ).

So, I know I need a new exhaust (entirely), so I was thinking of just welding a CAT in there when I do it. However, without the AIR pump, would that pass visual inspection? Even if I put a CAT in it that doesn't need / have provisions for AIR?

So, besides the exhaust, I'm presuming my heads have passages for EGR, and all I'll need for that aspect of it is an intake that has EGR passages, then the vacuum diaphragm for it, and I'll be good right?

I'm still really new at this stuff, but I have to drive 12 hours one way down to Georgia (I'm at school in Michigan), and I only have 1 chance to do this (between semesters). F@$k emissions requirements.

So, basically what I'm asking is:
-With a new exhaust, CAT, and EGR, will the car pass without AIR (presuming the inspector knows what (s)he is doing with a car this old)?

-To add EGR, what intake can I use? I know Edelbrock has a performer-style intake with EGR, but it says only for pre-86 motors (how do I tell what year my motor is from?)

 

First common-sensical piece of advice is, DON'T weld a cat in. They're a maintenance part. Definitely get one, just don't WELD it.

Second is, find out EXACTLY what they check there. Find out if they open the hood; if they do, what are they looking for; do they do a dyno test; if so what kind, or do they just sniff it at idle. Find out what the standards are for your particular car by its VIN (whether it's carb or FI, whether it's a 6-cyl car or a V8, or if that even matters), and post them. Search the user database on this site and private-message people in that area, if you have to; but without all of that info, anything you do, is just a blind guess, a stab in the dark. Not a good chance of success.

Third is, don't get all wrapped around the axle about EGR. Unless they specifically visually check it, it won't be an issue, with the super-low compression you probably have with those large-chamber heads on that small motor. It CERTAINLY isn't the front-burner issue right at the moment. Save your panic for something TRULY significant!!!

Fourth, what's your budget; how much work can you do yourself; and when is the deadline for all this? Why is this a priority right this moment? What's the grand occasion?

Fifth, tell us all the details about the motor you can; what cam, what carb, what intake, etc. Every detail, every part # you can. Some of those things might have to change, or they might not; or they might make it impossible, or just REAL difficult, or not have any impact at all on passing, or maybe even HELP. Pretty hard to tell you what to change, when we don't know where we're starting.

Calm down, take a deep breath, and approach it in a logical, disciplined, orderly manner. Make a list of the requirements, then a list of where you're out of line, then methodically attack those things one at a time. It might MAYBE turn out ALOT easier and cheaper than you think, if you are careful and wise in what you do, and not all scattergun and hysterical.

 

Thanks for your reply, here's what I know about the car:

It has a Holley carb (not sure what model number, but it does NOT have a float height adjustment, and does have electric choke). The car was originally a 305 Formula TBI. Upon further inspection, the intake is an Edelbrock Performer as near as I can tell, and I do know the cam is not stock (this is according to the prev. owner). It certainly isn't hot, and I don't know the specs, but its not stock. I don't think it should cause any problems, though, as it idles smooth as silk and I can't smell anything out of the tailpipe while it's running (even with no cat).

I looked up the GA emissions info, and according to their website the test will include a visual inspection of the CAT only, and then a simulated acceleration test (dyno test, 25/25 and 50/15) and a curb idle test.

The reason I need this done is that I only have a one week break every semester that I could use to drive down to GA and get this done, and I really don't want to end up waiting 6 months. I need this car GTG by the end of march.

So, after rethinking this it looks like I might be able to get away with just a new exhaust. I would take it to a shop for this, as the stock exhaust hangars are... well.. gone, and I don't have access to a welder (I'm at school). Any other work I can do myself, no problem. If I had access to a welder, I could do the exhaust myself too, but that's not the case.

Thanks for your input, I really appreciate the help. It looks like, seeing as theres no underhood visual inspection, I can get away with a new exhaust with a cat (welded to flanges and BOLTED in ) and a correctly-tuned carb. That's about 400$ cheaper than I initially budgeted! Maybe I'll put some 1.6 roller rockers in just as a primer on my valvetrain while I'm ordering parts. Anything I should look out for with regards to those? I know how to lash valves and install the poly-locks, all I need to check is what size studs I have, right?

 

OK, here's what to do then.

Buy yourself a cat for it, from Summit or some such. Should be no more than $125. Get the correct one listed for your car.

Buy a cat-back exhaust of your choice from a similar vendor. Hooker, Blowmaster, Edelbrock, Borla, etc. etc. etc.

Buy the hangers from a parts store. They're all readily available.

Install it all, or have it installed, WITHOUT welding. No welding whatsoever of any kind to any thing should be required, unless somebody has been hacking on the car itself, and it needs to be repaired. That way it can be easily (relatively) disassembled if the need ever arises in the future, without trashing the entire thing.

You have 3/8" rocker studs.

I'd recommend concentrating on the exhaust, all by itself, and see it through fully to completion. THen, if you have money and ambition left over, consider rockers. I'd put that aside for the time being however.

 

Ok, just one more question.. Say I wanted to put headers on the car at the same time. Could I get a cat installed after (downflow of) long tube headers? I don't see why it wouldn't work, I just wanted to make sure before I ordered anything.

 

Yes.

However, long tubes are probably a total waste, if it still has the stock heads. what little benefit they might provide will be voided by the heads. However, you'll still have to fight the relatively poor fit, ground clearance, etc.

I'd suggest getting one of the chassis-specific setups, specifically for one of these cars; Edelbrock and Hooker have them. If your budget allows, get the ceramic-coated ones. You'll be REALLY GLAD you did, over the long term.

Also, if you do get headers, then DO NOT get any exhaust parts (headers included) for a 305. Get the ones for the same year 350. Headers, cat, and a 3" cat-back. It all fits the same; the difference is, if you get the ones for a TBI 305, they will PRESERVE the bottleneck that makes that system so poor; namely, the small Y-pipe, cat inlet, and I-pipe. But 350 stuff will bolt right up and replace it all, as a unit. Just, not a piece at a time. It'll have to be all at once.

 

Cool, I just ordered Hooker 2055 headers (will have the AIR tubes cut off/welded shut), a cat and pacesetter catback, all for the 350 motor. Thanks for all of your insight, once I'm registered i'll start with a fat ol' cam and new heads, and see what happens. Hopefully I'll end up with a CR of over 9

 

Good way to fail inspection.

The cat needs OXYGEN to work. It can't turn carbon MONoxide into carbon DIoxide without an oxygen atom. Can't miracle that up out of nowhere. That oxygen comes from the AIR system. It'd be wise to leave it intact and operating, unless you want to go through this again.

Everthing else sounds good.

Good luck!!!

 

so how do you explain that the cat I found doesn't have air tubes?

or the fact that modern cars don't have air systems at all?

Also, the first post states that my AIR system is gone. Has been since I bought the car.

 

Lots of cats don't have AIR tubes. However the right ones for these cars, do.

Alot of modern computer-controlled cars are also tuned SO LEAN, that there's ALWAYS extra oxygen in the exhaust stream. It's possible to do that with EFI and still maintain some semblance of driveability; not so with a carb. After swapping the cam and putting on a carb instead of FI, there's not likely to be so much of that any more. Meaning, even the finest cat in the world, won't have the magic ingredient it needs in order to do its job.

Well if the AIR system is gone, there's not much else you can do; other than, hit the boneyard and scab one off of another vehicle. It's either that, or take the risk.

 

If your carb is tuned up properly, it should be able to pass a sniffer. Back when we had sniffers here, I've seen a non CC carbed, no cat, 350 C-20 Suburban (1983 no cats and no CC from the factory) pass a sniffer.

If your carb and general engine is in poor tune you will not pass, with or without the cat.