1988 Caprice - True duals

[Bob Ash]

Hi, does anyone here have a true dual exhaust on '88 or similar Caprice? I've bought a headers (Flowtech), mufflers and I wanna make up true duals ending in front of rear axle.
Pass side is ok, that's where the original exhaust goes. But on driver's side there's some crappy brace which apparently holds the tranny. There's no place to go over, when I go under I'll leave the exhaust on the first bump. So I've got to route the exhaust thru the current position of the brace. Is it possible to replace it with one that allows this? Have anyone done this before?

[silicon212]

You should be able to adapt a '94-'96 LT1 true dual/dual cat setup with almost no problem at all. I discovered that the LT1 exhaust manifolds should in fact fit a standard small block. You will need to obtain the entire setup, from the manifolds to the tailpipes, including cats (you will likely have to buy these new). You will also need to adapt the '94-'96 trans crossmember to the car you have - you need to weld an angle iron to the left frame rail in order to give that side of the crossmember something to bolt to - but that's about the only mod you will have to do. The rest is plug-and-play.

I went a single-cat setup, but fabricated a Y-pipe using LT1 components on my own car, which is an '88.

[Bob Ash]

Originally Posted by silicon212

You should be able to adapt a '94-'96 LT1 true dual/dual cat setup with almost no problem at all. I discovered that the LT1 exhaust manifolds should in fact fit a standard small block. You will need to obtain the entire setup, from the manifolds to the tailpipes, including cats (you will likely have to buy these new). You will also need to adapt the '94-'96 trans crossmember to the car you have - you need to weld an angle iron to the left frame rail in order to give that side of the crossmember something to bolt to - but that's about the only mod you will have to do. The rest is plug-and-play.

I went a single-cat setup, but fabricated a Y-pipe using LT1 components on my own car, which is an '88.

I'm not going to put an LT1 exhaust there, I'll use what I have - Flowtechs, Thrush Turbos and some 2 1/2 pipework. No cats, i don't need'em here (Czech Republic, Central Europe). LT1 setup is interesting idea, but it's easier to weld the tubing here, getting all that metal over the water isn't exactly cheap.
Only thing that worried me was that crossmember. Thanks for great advice - so I only have to figure out how to get an LT1 crossmember here. As far as I know, there are only two SS Impalas in our country, so I probably won't find one on junkyard.
Can I get order it as an replacement part somewhere? Looked for it at RockAuto, but with no success.

[capriceowns]

Have you tried eBay?

[Bob Ash]

Yup, I tried. Nothing.

Guess it'll be much faster to make a custom brace...

[ls954]

on all my other caprices the guy at the muffler shop was able to run the two exhaust pip down from the manifolds then run both of them down the passenger side, same route as the stock exhaust pipe goes under the cross member, and then seperate them after that point.

[400wagon]

check out this link. These are pipes that will have to be shipped, but I think they would be your best options

http://impalassforum.com/noncgi/ulti...;f=21;t=002719

The setup is made for the 94-96 impala ss, but it is 4 pipes, all mandrel bent 2 1/2 inch. I honestly think this is you best option for both price and performance. In the thread they call it the $215 catback, or "frankenstein catback" but it could be cheaper depending on mufflers and tips. They should fit your frame great and bolt up to your headers with very little modification - if your taking it to a shop to get it welded, they could handle it pretty easy.

As far as the crossmember goes, they do sell tubular cross members, or you could modify yours or fabricate one since you don't really have access to an lt1 crossmember. I modified a crossmember for dual exhaust on a malibu I had once -- didn't cost anything and only took an afternoon a friends house-- we cut a notch out of the crossmember where the exaust needed to be, then welded a thick steel plate to the top. it works best if the plate on top is bent in a c shape around the top of the crossmember to give it some more rigidity -- if not the crossmember will bow.


the crossmember actually took me 2 tries to get right. The first time we didn't bend the plate in a c shape, and I went over some railroad track really fast and the crossmember sagged and my driveshaft rubbed on a bracket on the bottom of the car.

For where you are at, and the options you have available, I think these may be your best choices.