ragingbull

The new 400ci engine is the 1980 vette with the new coated headers. Now time for an exhaust system. Looked in many of the mags and catalogs and all I can find is Mid Americas true dual exhaust set up. It is not a manderal bent system and runs both pipes down one side of the car thus making one side quite a bit longer then the other. Is this even worth using? Heard from a friend that you can use a older C3 crossmember and then get a very nice flowing exhaust. Any opinions and or options that might work, or am I just full of it and just go and use the system from Mid America. Any help would be greatly appreciated...

Avette4me

Welcome to the forum, you will find a lot of very knowledgeable and helpful people here. I know I have.

I have seen the system that you are talking about and chose to go a different route. I took the cat off and tossed it. Took the car to a local muffler shop and ran duals straight back. The drivers side pipe runs under the cross member and I still have about 4” + clearance. Haven’t had and problems dragging it yet (or any other problem for that matter). I suppose that there is a possibility that I will be someday forced to add dual cats, but I intend to wait ‘till that happens.

I’m not sure if the old cat was plugged, but I am sure that I increased the horsepower in my car. In retrospect, it seems like it was being choked to death. What a difference.

Anyway, that’s my two cents.

ragingbull

Thanx compadre for the reply. No cats on this cats vet either no need in my area. Anymore info would be great...

The_Dude

I've been wondering the same thing. I have an older auto xmember sitting in my garage, but I don't know how much hassle it would be to install, especially with a manual trans.

Ryan77

I put headers, true duals, no cats, an X-pipe, and Flowmaster 40's on my '77 that has a manual trans. There was already 2 existing holes in the crossmember for true duals, so it was very easy to have done by my mechanic. I'm not sure if the crossmember in my manual trans. '77 is different from yours though.

The_Dude

Yes it is. That's the problem. The '80 manual trans cross member isn't welded, but it doesn't have the two holes for dual exhaust. Rather, it has an indentation on the passenger side for the single exhaust with cat. The Mid America system runs two pipes through this indentation, which makes the drivers side pipe longer than the passenger side. It's probably not that big of a deal for most of us. I just think that it looks cleaner with the older cross member. :cheers:

Ganey

The dual ex. type 68-79 rec. for performance.


Ryan

Yours is different- the dual ex. crossmember.

MotorHead

Run them down the paseger side it works great trust me, if one pipe is a little longer that the other so what ? :D

The_Dude

Yeah, I think you're absolutley right. That's what I'm going to do, unless I can install the older cross member easily. Since the car is a driver, it's not really that big of a deal. :cheers:

MIKER

Here is one of many options:
We notched my OE cross-member for dual exhaust. The notch was created by cutting a semi-circle out and filling it with a section of 3" exhaust tubing sliced in half and welded in.

BSeery

On my 1980 I am going to change the crossmember with one of the older models. I have to run cat's and don't want them all on the passenger side. I am just going to swap out the crossmember and do it that way.
I will try and get them to put a H-pipe in if there is room.

kgraumann

I have the exhaust your talking about, and have installed it. I was not impressed with it, and will choose not to use one again. It was a total headache to install. Then when I finally broke down and took it to my exhaust man and explained how cheap I was trying to be, he laughed at me.

By the time the job was done, I had spent more money trying to save money. So the next time I install an exhaust on my 1980, I will have a professional do it.

Gator81

I know one member on here, UKPaul, has that Mid-America dual system on his '81, and he has said he likes it. Perhaps he'll reply to this thread. You might try emailing him.

Twin_Turbo

the older style crossmember isn't a bolt in install. The bolts on the bottom of the frame rails will line up but you need to modify (elongate) the ears on the crossmember to get the pin through (inside of frame)

Marck

The Money Pit

I've got the MAD stainless dual system on the car for seven years now. I don't care for the both pipes down the passenger side trick,but can report the system with headers and the 406,will pull an easy 6000 rpms,so I don't feel restriction is an issue. The problem I have is trying to keep the pipes up tight to the rear end,where they pass under the spring mount. I've even welded the pipe joints and after a short time,the pipes seem to sag a bit. Not a clearance issue at all,just feel it looks like they could be up tighter to the rear.
If money were no object I'd do Hooker sidemount headers and pipes! :cool:

Fasteighty

:iagree:

I have the MAD dual exhast kit installed on my 80 that I bought off of a forum member. It was a piece of cake to install, sounds great and boosted the HP once I ripped the cat off. I can send you some pics of what it looks like. Email me and I will send them your way.

UKPaul

I put the MA system on my '81 (Hi Gator :thumbs: ). Fitting it was easy, but you must fit the whole system loosely in place & jiggle it about to get the best fit b4 tightening it all up. The only problem I had was that the p.side muffler was being pushed too far outboard by the MA system. After various bouts of jiggling, I decided that it wasn't me getting it wrong (like normal :D ) & sawed about 2" off of the end of the pipe. Muffler fits fine now. To prevent any problems with working loose I got a pair of ordinary "off the shelf" rubber exhaust straps from an exhaust shop & bolted one end of each to the chassis using the bolts that held the original exhaust hanger. I then used large hose clips to hold the end of each strap to the pipes, with the straps under very slight tension. It works well & stops the exhausts from sagging & clanging together when I drive down the open cast mines we have here (officially called "pot holes").

As Marck said, fitting the earlier x-member isn't a staight forward swap out.

The d.side pipe, by the route it takes, is longer than the p.side & has bends in it. No doubt this will lose some power but, unless you've gone OTT in getting max power from your engine, I wouldn't worry about it. Fitting the MA system gave me a far bigger seat of the pants power increase than any other mod I've done to the car. It really needs an "X" or "H" pipe to balance out the exhaust pressures & help prevent the pops on the overrun. I'm making up an "H" pipe at the moment & intend to fit it at the point where the pipes in each side of the system join (the MA system has 2 pipes/side). This will also help keep the system more rigidly held in place & if I can use a hanger to hold the "H" pipe to the chassis then it'll be a bonus.
I'm very happy with the system & it certainly cost a lot less than I would have paid to have one made here (even allowing for shipping, import duty, tax.....).
:cheers:

Bobchad

True duals on a 77 with an H pipe.
http://home.attbi.com/~jchadwick/exhaust.htm

TedH

I tried the true dual exhaust from Mid-Am for the early C3 (pipes pass through the x-member). I had a custom cross-member that came with my 700R4 and figured the pipes would not be a problem. Was I ever wrong... that system soon became scrap.

I was also considering the '82 dual exhaust that snaked to the right side (in event cat was ever required, the two pipes would be there). Somebody on the forum warned me away from them as there were clearance problems at trans cross-member.

I finally cobbled together two sections of pipe from the kit that I bought from Mid-Am and ran them off of the headers (straight pipes, no mufflers god-awful noise) and drove the car to the muffler shop. Ran aluminized 2.5" dual exhaust pipes off my headers straight back (slight bend at transmission to keep the pipes away from the transmission) and then 90 degree bends to the mufflers. Watching the guy fit and bend the pipes, I could tell he was a pro. He welded it all together (no more el-cheapo clamps and leaks for me) and included chrome tips for about $240 'out the door'. Good deal in my opinion and the pipes are 'welded one-piece' from headers back; makes removal/re-installation a breeze.

Twin_Turbo

82 dual exhaust? 82's didn't have duals.