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Interesting concept on an assist approach. Anyone have any experience with the item or comments?http://ecihotrodbrakes.com/universal_brake_assist.html

Probabaly requires a very long pedal Travel. Most likely just fine for the OEM 55/56 brake pedal assuming it is mounted in same position and connects to pedal as OEM Packard. Pedal probably has to set 4" higher than OEM.

THen we're back to square one if replacement parts are needed 10 to 20 years from now.

I called and talked to these folks. They said that it doesn't increase pedal travel and the response is linear. The unit is about 16" long and it has a Chevy M/C (unit and M/C come as a set). Price is $395.

16 inches might be a problem on the frame rail but probably overcome if the unit works as advertised. I believe a remote fill would take care of some of the issue. Some linkage design though. $395 is maybe a bit pricier than vacuum but not as high as other options.

Did they give any indication of suitability for our needs or is that unit designed for a specific disc/drum setup only. Would be nice to find other options besides the current make your own approach or the not quite bolt on $1200+ Electroboost.

The vacuum setup is only a few inches shorter but so much wider. Getting the space and mount for the proper ratio with our stock pedal setup and still looking somewhat factory is our hardest issue. It's difficult enough on a wide firewall. No idea on a narrow prewar unless something goes under the body.

Would the 16" be a problem if mounted verticle???

From the website description:
". Used in conjunction with the supplied master cylinder the Universal Brake Assist yields a 100% increase in system pressure compared to typical unboosted 1 inch bore master cylinder"

But how does that compare to a boosted power system???? I don't know. I'm guessing a boosted power brake is at least 400%, not just 100%. Altho that may be just fine for those that do not like the sensitivity of the 50's thru 70's power brake systems.

As some of you may know I put a Chevy dual chamber M/C on my 38 Jr.without too much trouble. Without much more fabrication I could install their unit- there is enough room. I would only have to whip up a bracket to mount it to the frame. The guy also mentioned to me that some other company makes banjo fittings that go on the M/C so that would make brake line routing easier. I had to make some tight bends on my setup. I heard from someone at a car show that my first idea of a 7" booster really won't do much but who knows. BTW the 7"single diaphragm is only about 3 1/2 " long

Claims of No external power source needed as well as no increase in brake pedal travel leaves me skeptical that it is no better than an unboosted 1" bore system.

There is some untold "rest of the story" here that we need to know.

Most basic FUndemtal law of physics:
Energy can niether be created nor destroyed.

There is more that we need to know bout this particular set up.

As I understand it, the pedal ratio and your foot's input pressure is key to the output pressure. The vacuum booster only adds a set amount depending on several conditions. Once that set amount is reached there is no more to give.

Here is a partial chart giving calculated additional pressures for booster sizes we can accommodate. Threw in the 9 so as to interpolate for the 7" dual and 8" which is about all we can fit. Various vacuum conditions and assuming 100% efficiency. The article mentions that 85% efficiency is more the norm to be expected.

ECI also has a "brake pressure multiplier" in which a dual size piston setup increases pressure at slightly less volume. That one does require a longer pedal travel.

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Wait a minute. I think i figured out how that ecihotrod system works:

Probably works like a two stage hydraulic jack. A fast low pressure circuit with slow high pressure circuit.

One piston piston moves the brake shoes real fast out against the drum until a cetain amount of pressure obtains. Then the sudden increase of resistence pressure causes a shuttle valve open to a much smaller piston allowing less foot pressure to create greater pressure in the line but over much less travel because the lost motion between shoes and drum has already been taken up by the fast circuit..

Just like a two stage hydraulic jack works.