Are any of the shorty headers still available for our cars shorter than the others? I'm making my own dual exhaust system, and the shorty headers I'm using have collector flanges that set too low for my taste. I can't get down pipes with a radius of 4" coming out of the collector flanges from dropping down too low. The right side seems to be worse.

I know the shorty headers for our cars are designed to be used with a Y-pipe, so the right side down pipe just runs straight down into the pipe coming from the left side, but I'm not making or using a Y-pipe so I need the collectors to be as high up as possible so I can connect my 4" radius down pipes to them without them sticking down below the subframe rails, which messes up the ground clearance for everything else in the exhaust system..

Thanks for any answers to my question.

 

Maybe look at Hooker cast manifolds instead of the actual headers. Depends on your performance goals though, not as good as headers for sure, but better than stock iron manifolds. Hooker 8525 or 8527 (from Holley now-a-days.)

 

I'm starting to reconsider the Y-pipe thing. I might be better off with a Y-pipe and a 3" single pipe to the back of the car than trying to run two 2.5" pipes and having poor ground clearance. I know the topic of "true dual exhaust" has been beat to death in this section. These cars obviously were made to run two pipes to the back because of all the many obstacles in the way.

 

If you are going to run duals you should start with long tube headers. Having true duals myself, I would start with a set of long tubes, y-pipe into a 3.5" or 4" mufflex system. The duals are not worth it.

 

I have a T5 transmission, so how do you get thru all the hydraulic clutch mess with long tube headers? Also, how do you get past the transmission crossmember without having to drop your pipes down closer to the ground to go under it? The only way I can see to get the pipes to the back of the car and keep them fairly close to the body (without having to modify the floor or crossmember) is to use the factory routing where everything goes down the right side of the transmission/driveshaft.

 

This is why they are not worth it. Even if you alleviate the two obstacles you bring up, T56 and Holley xmember, there is still a lot of work to do. I honestly forgot about the T5 hydraulics but the cross member issue is no mas with the Holley blackheart unit. So I guess I take that back on headers, and shorties are better than nothing if there aren't a set of long tubes that clear the clutch. If you are dead set though, there is no need to cut the floors.

 

When I bought this car it had a 3" Magnaflow system grafted onto the original beat up Y-pipe with a 2.5" pipe (to replace the converter) and a bunch of very poor welds. I've thought about just reusing as much of that as I can with a Y-pipe (I make) to go with my shorty headers. That would be a huge improvement over what I had, but really I would like two pipes going all the way to the back.

I looked at the Blackheart sytem, too, to get inspiration. That's what made me think I could run two 2.5" pipes to the back of the car using the stock routing once I got past the transmission.

 

What size and power level engine is going into your car?

 

It's a 350 SBC carbureted truck engine. Right now it's fairly stock, but eventually it will have better flowing heads, an LT-1 spec cam, Holley double pumper and an Edelbrock Performer RPM intake manifold. I don't know where that will put me horsepower-wise.

 

Does anyone have information on where the collectors of the Hedman 68470 headers end up when installed, or pictures? They look just a tad different than what I have, but it's hard to tell just from pictures of them alone, uninstalled, how they would fit. They have ball and socket collectors, which I think is a good idea. Almost every other shorty header available for our cars the solid flanges, which I think is a little uncouth.

 

I forgot that they went ball and socket. I have always cut off the stock flanges and welded on v-bands.

They dump out next to the oil pan, just high enough that you can get a 2.5" bend in under the pan from the driver's side. The driver's side one is really close to the back of the stock K-member.

For what you're talking about building I don't see a real reason why you'd need anything more than a decent aftermarket system that uses the stock routing.

 

Do these actually fit in our cars?

 

As I mentioned above the passenger (I call it right) side collector is the bigger issue than the driver side you described because on my headers it sits pretty low. Since pretty much all the other shorty headers available for our cars look similar to mine I suspect they all have that problem since they're clearly made for the single exhaust system our cars originally had.

I just don't consider single exhaust systems for V-8 engines to be performance exhaust systems, no matter how overpriced they are as the ready-made ones for our cars are. The Y-pipe is going to be your first restriction, then the next problem is you can only run so big of a pipe (3") to the single muffler in back, which is a restriction in itself. Even if you have to drop down to a 2 1/4" pipe size on a dual exhaust system to be able to run two pipes close to the undercarriage from the engine to two mufflers and tailpipes in back you're still better off, performance wise.

 

A single 3" system can support 400 rwhp. The exhaust only needs to be big enough to support the power the motor is making. Dual vs single doesn't matter. At lower power levels you can make a non restrictive y-pipe. If you are able to run longtubes (still unsure if there is a set that clear the T5 hydraulics) you can make a nice y-pipe (not in the OEM traditional sense) that merges into a single system. Hawks sells a kit like this.

 

Dynomax 2.25" Header-Back Dual Exhaust Kits 89009


Discontinued - Dynomax Performance Headers 85012


Summit Racing - Dynomax 2.25" Header-Back Dual Exhaust Kits 89009

Discontinued - Summit Racing - Dynomax Performance Headers 85012

Summit Racing - Dynomax Super Turbo Mufflers 17731

Summit Racing - Dynomax Ultra Flo Welded Mufflers 17217

This might be a good jumping off point for you to install a true dual exhaust system on your car. I expect there will have to be some tweaking and adjusting to this to fit your headers and car to your liking.

Installation Instructions - Dynomax 2.25" Header-Back Dual Exhaust Kit 89009

 

The problem is usually not one of ground clearance with passenger side shorties, but one of when you make that tight bend you get close to the control arm bushings and plastic fender liner. The fender liner can be sacrificed/trimmed, but a poly bushing will be ruined.

Well there you're just plain wrong both math and physics wise

Math wise, the section area of a 3" pipe is about the same as 2 x 2-1/8" pipe, and if you account for wall thickness its about the same as 2, 2-1/4" pipes. But physics wise, flow is proportionate to the drag (friction) of the airflow against the walls of the pipe and the bends. Since 2 pipes will have more wall surface area for the same section than one, the 2 pipes have to have more section area than a single 3" pipe to flow the same. So for practical purposes, a single 3" pipe typically will flow what 2, 2-1/2" pipes, sometimes better.

You mention y-pipes. Like collectors (4 pipes coming together), y-pipes can be designed to scavenge the other leg increasing total flow. Flowmaster sells y-pipes that do just that that you can use to build your exhaust. Mufflers can also be a major factor. First, the further back you put them the less an effect they have on restricting flow because the exhaust gasses have cooled and lost more volume. Secondly, the larger the overall volume you have for a specific flow the more effective things can be without hurting flow, and no matter what given a specific available space one large muffer will use that space more efficiently. Finally, design can go either way. I'd suggest the largest, longest straight-through muffler that maintains tube size, again favoring the single exhaust because it just gives more room for an effective design.

 

Okay. I'll give that some thought. Thanks.

Now I'm back to considering rehabilitating the butchered up 3" Magnaflow exhaust that came on my car. It looks like it just needs a 45 degree 3" elbow to replace the mangled front piece of the system to get it close to it's original catback form. I still would need to make a Y-pipe, though, but I have a start on that with what I have started for the system I was originally going to build. If my Y-pipe has 2.5" downpipes is it best to transition to 3" BEFORE you get to the passenger side downpipe? That would make the most sense to me, so you don't have a bottleneck where both sides of the exhaust have to go through one 2.5" pipe (like the stock Y-pipe) before it can go to the 3" pipe.