Stock crossmember for 76

[vetteengnr]

I'm in the process of installing true dual exhuast on my 76. I have run into a small problem ad

Does the stock crossmember for the 1976 have two completely open holes for the exhaust to run through?

I know quite a few of you on the board have installed true duals on a later model C3, did you run both tubes through the crossmember?

I have a small plate that is welded to the driver side crossmember hole that is holding a pulley for the brake system. The plate obstructs the crossmember hole so the exhaust pipe can not run through. I called Mid America and they thought the pipe was supposed to run through the crossmember. I haven't tightened up the manifold connected pipe, but it looks like if I did the pipe is going to have to fit through the crossmember.

 

[Bob Chadwick]

The 77 does. I would assume you have the same frame.

What are you going with?

I have read the posts on true dual exhaust and decided to stick with my stock ram horns for now on an unmodified engine. I'm going to go with 2 1/2 inch pipes with either an H or X crossover, remove the cat and change to the 50 series flowmasters.

I looked at the kits at the various sites and they appear rather expensive. I think I can do better by just going to a shop, there is supposed to be a good one here in northeast Atlanta, and having them fab the setup.

Any thoughts?

Bob

 

[vetteengnr]

I bought the true dual setup from MidAmerica, 2 1/2" Manifold back. It is not that bad of a price considering you can bolt it on straight out of the box. Unless, of course, your car has been tampered with like mine. :bash
I haven't decided on mufflers or headers yet, but I'm thinking dynomax ceramic coated headers and dynomax mufflers. I like the flowmaster sound, but I hear too much of it.

 

[Bob Chadwick]

I received a surprise today, the shop won't remove the cat. He also said they could not do exhaust work on a cat equipped car if one was not in place. I guess I shouldn't be surprised by this considering the air quality in Atlanta. They did offer to put on a dual cat system with a crossover for $800. I guess I'm back to square one.

Vetteengr, which of the Mid America systems did you get, the one labeled 1956-79 Dual Exhaust in Custom-Built Aluminized or Stainless Steel, part #603-840 on page 72 of their catalogue? Other than the problem you elaborated was it an easy install? Are you going to be able to add a crossover pipe to the system?

I'm a little concerned about going without a cat if muffler shops won't work on it.

Bob

 

[SteveW]

Mid America Dual Exh. Systems

Our Dual Exhaust Systems for the 1975-up Corvettes are for off-road & race use only. Do not remove any catalytic converters or pollution control devices on your street cars. We do not advocate this at all.

We do carry high flow EPA certified converters that will enhance performance & still allow you to remain compliant.

Thanks!
Steve Wiedman
Mid America Designs

 

[rpounds]

I used a straight through cat design on my '75 and am happy, happy, happy :s

The previous owner had installed a dual exhaust system in place of the original exhaust. In order to be smog legal in California, I had to go back to a basically stock configuration. The straight through design is great!!

The added benefit to retaining a cat is that the exhaust doesn't stink. Before I put a cat back on, I couldn't stand to let it idle in front of the house. My wife complained, the kids complained . . . even the dog complained

Now, she smells sweet . . .

 

[vetteengnr]

Hmmmmmm.......
Here in Texas all I smell is sweat.

Seriously though, I already get complaints of my car smelling without any exhaust modifications.

So you have 2 cats on your car rpounds?

 

[rpounds]

No. I have only one. It is a one into two design, so that a stock crossover pipe can be used and then split back out to the mufflers. That way, you don't have to use that funky 'Y' pipe in the rear that is common to later C3s. That thing has more bends than a dog's hind leg and has to be pretty restrictive. This is the only way that is technically legal here in California. I don't remember for sure what the inlet and outlet sizes are, but I believe that they are 2 1/2".

 

[Jack]

/Bob ... I received a surprise today, the shop won't remove the cat. He also said they could not do exhaust work on a cat equipped car if one was not in place.

I plead ignorance of Georgia laws. That said, if you can operate/inspect/register your car WITHOUT running afoul of the law in your area ... then maybe you have a couple options for cat-free exhaust. Check with local race car fabricators/shops ... or consider contacting a Midas etc in a neighboring state (SC is VERY liberal ... NO one looks or sniffs ... yet).
JACK:gap

 

[Bob Chadwick]

I'm still looking. Thanks for all the advice.

Can someone post a picture of a true dual exhaust from a post cat era C-3 showing how it was setup?

Bob

 

[fasterthanu]

*Check local Emission Laws* I live in Illinois. The books show, that for a 1976 corvette, I believe up to 78 vettes, that for a FACT, you do NOT need Catalytic Converters on for emissions test. If you go to your local facility, they CAN look it up for you. If it shows the same as out here, have them photocopy it, and bring it to the exhaust place. It will be no problem. And yes, there are two holes drilled in the crossmember =)

 

[fasterthanu]

if you ask them, they will say "Yes you need one." You would be surprised. Have them look in the book in front of you and show you. If the book says you don't need it, then they CAN"T test you for it =)

 

[Bob Chadwick]

I don't even need emissions testing. The muffler shops are reluctant to do anything with or to the cats, other than replace them with the same thing, for fear of a $10,000 fine from big brother.

I have got some other places to follow with, thanks to some help I received here.

Bob

 

[MoeJr]

Could you maybe run the better 80-82 front pipe with 1 hi flow cat and then split it into duals? I believe the 80-82 front pipe runs thru both holes in the crossmember then goes to 1 cat and splits into duals. May be a bit less restrictive than the stock 76 Y pipe that goes thru only one hole and makes that 90 degree bend from the left manifold. Just my .02

 

[78SilvAnniv]

I was told...

When we first hit town here in Georgia (moved from Washington state, muffler fell off 78 in TX) I took the 78 to the local muffler shop, unloaded her from the trailer and asked for dual exhaust.

They said they couldn't do it, even though there are no emissions testing in our county. Well, 78 was the only vehicle we had to drive besides the motorhome (and we had to live in that) so I told them I needed to have her operable as she was our only form of transportation until we could buy another vehicle for the husband.

When I was in a local speed shop and griping to them about the exhaust not being able to be done the way I wanted...I WAS TOLD... that THEY can't remove the cats due to huge fines...but if I removed the cats BEFOREHAND I could have the exhaust done the way I wanted.
Perhaps you could check into that? I'm am also cursorily interested in fasterthanu's tidbit regarding no cats being required for emissions testing. I wonder if that is just a state thing, because I'm sure CA required them when we lived there.

However, next year 78 will be age 25, and won't she be exempt from emissions testing ANYWHERE after that?
Heidi

 

[Bob Chadwick]

Heidi,

Your right on the 25 year thing. I had no smog testing in metro Atlanta this year. When I had my legend checked, they did a visual to make sure that all factory original stuff was there. Now could the high school kid miss something small and out of the way, sure, but I doubt he would miss a catalytic converter.

The reputable shops I hae talked with here won't touch the car without cats, no matter who takes them off.

I'm kind of leaning towards duals with two cats. One shop has said they will do that while others have said they will only do the same set up that is on the car.

Bob

 

[77-4speed]

Heidi,

Your 78 still won't be exempt in CA! They make you wait until the old 35 rolls around. That's right, your car has to be 35 years old to be exempt from emissions.

Smog-Nazi's.

 

[rpounds]

However, next year 78 will be age 25, and won't she be exempt from emissions testing ANYWHERE after that?

In a word 'no'. Here in California, there is no testing required on vehicles manufactured in 1973 or earlier. '74 and newer has to be tested. There is absolutely no way, regardless of what else has been done to the car, that a '75 or newer vehicle would pass emissions testing without an operable cat.

Ron

 

[78SilvAnniv]

Just one more reason...

...I'm glad we moved to Georgia!
Sil

 

[rpounds]

Sil,

Move over!! The way things are going here in California, I may join you folks down there in the deep south one of these days!!

But, if you could do me a favor . . . make the weather a little better