what in the sam hill do these do? Power stacks?

[dusterbing the peace]

It talks about springs in them…I think they’re just a pressure spring that allows exhaust out when exhaust pressure gets high enough, basically a relief path and/or pressure regulated cutout. Not gonna do much with a 3/4 pipe, but hey, line up for your snake oil!!! They also have a filter, probably for “EPA compliance”

 

[AJ/FormS]

Before you say the exhaust manifolds are always under pressure, consider how exhaust "aspirators" work.

 

[67Dart273]

Never heard of 'er

 

[cudavert]

I'll bet the occupants got a nice steady dose of exhaust coming in through the cowl/vents too. "I'm getting sleepy!!"

 

[dart4forte]

Imagine the liability and class action suits if someone tried to market this item in this day and age!

Market them to the EPA or better yet the CARB in Cali. Reduces green house gasses

 

[PistolGrip]

As a young, impressionable (but I repeat myself) teen, I'd go through the JC Whitney catalog to plan how to make my car if/when I got one - the coolest/fastest thing around. This would have made my list.

 

[Swinger 340]

Air passing through a restriction experiences a pressure drop.

Besides, I didn't say they work, I just said what I thought they were designed to do.

The first CO2 sensor

 

[65TerrorCuda]

So these things are just exhaust cutouts? Wonder how many got installed

 

[Dale Davies]

How can that happen? Exhaust is pushing air out on that part of the engine cycle. Maybe leaning the fuel mixture out somehow? I'm guessing ?

When the exhaust valve just opens there is still about 100PSI in the cylinder. This roars past the exhaust valve at supersonic speed. Although we do not normally feel it, air has mass as does the exhaust. That mass and velocity creates inertia as that slug of exhaust roars down the exhaust pipe. When the exhaust valve closes, this creates a low or negative pressure in the exhaust. I assume these had a check valve in them to prevent exhaust getting out.
The early emissions cars had air injection pumps and a passage in the head or tappings in the exhaust at each port. The carbs were jetted rich to provide unburned hot fuel that just needed more air to burn again in the manifold. Then they went to a gulp valve system with a check valve. When the exhaust pressure went negative the check valve opened and let in a bit of air. No expensive and bulky air pump.

 

[Mr. PNW]

It sold as I was reading this

 

[Super-Cuda]

When the exhaust valve just opens there is still about 100PSI in the cylinder. This roars past the exhaust valve at supersonic speed. Although we do not normally feel it, air has mass as does the exhaust. That mass and velocity creates inertia as that slug of exhaust roars down the exhaust pipe. When the exhaust valve closes, this creates a low or negative pressure in the exhaust. I assume these had a check valve in them to prevent exhaust getting out.
The early emissions cars had air injection pumps and a passage in the head or tappings in the exhaust at each port. The carbs were jetted rich to provide unburned hot fuel that just needed more air to burn again in the manifold. Then they went to a gulp valve system with a check valve. When the exhaust pressure went negative the check valve opened and let in a bit of air. No expensive and bulky air pump.

If the stacks did indeed have a check valve, that explains a lot.

 

[74Scooter]

When the exhaust valve just opens there is still about 100PSI in the cylinder. This roars past the exhaust valve at supersonic speed. Although we do not normally feel it, air has mass as does the exhaust. That mass and velocity creates inertia as that slug of exhaust roars down the exhaust pipe. When the exhaust valve closes, this creates a low or negative pressure in the exhaust. I assume these had a check valve in them to prevent exhaust getting out.
The early emissions cars had air injection pumps and a passage in the head or tappings in the exhaust at each port. The carbs were jetted rich to provide unburned hot fuel that just needed more air to burn again in the manifold. Then they went to a gulp valve system with a check valve. When the exhaust pressure went negative the check valve opened and let in a bit of air. No expensive and bulky air pump.

Yup, my 67 Fairlane (CA car so... smog)had the air pump and injectors on the exhaust ports. You can see the threaded holes the air injector rails screwed into just below the valve cover lip in the photo below.

 

[RustyRatRod]

Yup, my 67 Fairlane (CA car so... smog)had the air pump and injectors on the exhaust ports. You can see the threaded holes the air injector rails screwed into just below the valve cover lip in the photo below.

View attachment 1715982546

I see they have the extra exhaust mannyfold bolt holes. 390GT? 428?

 

[74Scooter]

I see they have the extra exhaust mannyfold bolt holes. 390GT? 428?

390GT 67 Lane GTA.... I used black ox capsetscrews and permatex hi temp sealer on the injector holes. They sit flush and you'd hardly notice them.

 

[Jean Genibrel]

Never heard of these before,

ODD vintage NOS hi-po car POWER STACKS Ford GM/Chevy Mopar hot rod MINI HEADERS | eBay

Ah yes, the fine needlework of advertising men!