i bought the two gallon kit form hornblasters and this is how my girlfriends dad and i installed it
I mounted the compressor perpendicular to the frame rail and the cab up towards the front of the truck
mounted the tank behind the compressor
1 pair of horns behind the tank
pair 2 behind the first pair
I used that angled metal with the holes in it to run along the frame rail and the cab, i used the bolts for the tube steps on my truck for the piece of metal against the cab and i drilled and tapped the frame and bolted the other piece of metal on the frame rail,
then i used two pieces of flat stock to drill holes in and mount the compressor and the tank on on top of the two metal pieces.
The horns are very light so i mounted them to the frame rail using self tapping screws and the metal with holes in it
before you mount the tank make sure to attach all fittings into the ports on the tank and the compressor hose to the tank.
after everything was mounted i spliced a wire into the positive lead of the stock horn to a toggle switch and from the toggle switch to the valve that would open the air from the tank to the horns. - this will allow you to use your stock horn button to honk the train horn and your regular horn at the same time, and when you want to flip the switch and you have just your stock horn back.
Next i hooked up a wire to an ignition source and ran it to the relay, after that i ran a fused 12v wire to the relay. use the ignition source or the compressor will kick on and kill your battery
from there i ran a wire from the relay to the pressure switch and to the compressor - all of the relay and pressure switch work cuts the compressor on when pressure goes below 115psi and cuts it off when it gets to 145psi
after this you ground the compressor and the valve
then i took the air hose, ran it from the tank to the valve from the valve to the manifold and from the manifold to all of the horns
lastly i put on my filter and i just pushed it through one of the holes on the metal that i installed
NOTE eveything will be tight but it will fit
after all of that VIOLA! completely hidden triain horn
videos soon (as soon as i can get away from my schoolwork for a while)