sounds like the valve in the booster is sticking, could try and disconnect the vacuum line and see if it still happens with it sticking,if so could be a broken spring in the booster or rust in the cylinder of the booster causing the seal to get stuck or old brake fluid that has been sucked through the front seal of the master cylinder, which is really not good, can lead to total brake loss, as the vacuum will suck all the brake fluid out of the master cylinder into the brake booster without warning..

one other thing that causes a low brake pedal is the residual valve leaking back, its a small check valve in the end of the master cylinder, that keeps around 10 psi in the brake lines all the times.

i have also found it a good idea to solder another wire to the top of the sending unit also 18 guage long enough to ground it to the trunk latch bolt,,then you dont rely on a good connection between the sending unit and tank, of the top of the frame.

are you having problems with it getting stuck in park? talk tohttp://www.ultramaticdynamics.com/ the last one i did it seemed like the cam that pushes the parking pawl travels too far, then has to push the pawl back up then drop it down to clear the gear.., Talk to peter finch..

one thing you mite try is take the line going into the fuel pump and run a hose into a jerry can and see what happens, i have heard of when the seal the gas tanks , the the pickup tube gets also covered in sealent causing problems. Also try blowing the line out too and see if its got any crap in it too.

problem with the packard is the front springs sit up in a pocket so far, and there is no room to get a spring compressor on the outside, to unload them enough. and internal type may work

one of three things, disconnect the wire(s)inside the distributer going to the points, now check the the condensor lead to ground on ohms, it should show open. then check from the terminal on the side of the distributer to ground, should also be open,(i have seen the wire from the terminal to the points, get chaffed, and short to the base plate, if so replace the wire, cant see the insulator on the points going. the distributer is not a complex thing, if you remove the distributer, line up the rotor to the case and mark it before you remove it. Something is shorted in the distributer, just a matter of figuring what it is, i would be thinking the condensor, or the lead in wire chaffed or the lead in wire touching the base plate at the points.

almost sounds like the front pump is not working or feeding the converter,did you reinstall the oil transfer tubes, from the front pump to the oilcooler? 2 1/4 inch tubes about 2 inches long? have you checked the test port on the bell housing for pressure? how is the snow there?

i had to also replace the ends on the cooler, i used exhaust adapters, then used the expanded section , and cut a sliver of it off and braze it on by the end to hold the hoses on .

It is 1/4 20 , but is does have a jog in it, not too hard to do a double bend in it to .