TSB for Fuel Pump Bypass Kit?

Recently had some vapor lock on hot afternoon with winter fuel. So while looking over the situation, I dug out this Chrysler fuel pump bypass kit to see how it worked.

There is a second code on the box that looks like it could match a TSB, 14-73-3. My first guess was a TSB for fuel in 1973. But not turning anything up on Hamtramk-Historical. As far as I know, this kit was a Chrysler fix done by dealers.

Q1. What was/were the original applications?
I've been told two different things, both could be true.

Q2. What does 14-73-3 represent?

Background:
Bought this kit years ago based on a suggestion from a Chrysler parts manager when mentioning possible fuel issues. He rattled the part number off the top of his head- 2830 292.
IIRC he said it was a Chrysler fix for vapor lock.
Based on the instruction sheet at least one use was to prevent flooding from vapor lock between the fuel pump and the carb(s).

One more observation. The part number seems low for 1973.

The kit was originally listed for use on '65-'68 Dodge trucks, vans and wagons with the /6. '69 CHP 440 cars had it installed.

The nipple for the crossover hose has a tiny orifice that allows fuel to loop around from the pressure side of the pump to the suction side. The small amount of fuel bypassed doesn't affect performance but it does allow trapped pressure in the fuel delivery line to bleed off after engine shutdown.

The 1973 TSB probably advised the use of an earlier kit to solve a later problem.

John,
Thanks! Do you know if these were these dealer installed?

My memory was that the parts manager said something about being for slant six a-bodies, but that was real fuzzy. Another person recently mentioned it was a fix for long ram engines, which is plausible, but the p/n seemed a bit high for early 60s.

I was just guessing about the 73 in 14-73-3 representing a TSB from 1973.
In the parts books, 14-73-0 is the fuel pump diagram reference so maybe it relates to that??

14-73-3 has nothing to do with the date. it is the reference to the location of the part in the parts book. 14 is the fuel section.

Yes, but its unusual to see reference number with a part, and that reference number doesn't show in the two parts books I have. That's why it seems likely there is a TSB or a part's book supplement. Because for some reason it was deemed appropriate to add the reference number to the box, when normally it wasn't (at least to the best of my knowledge).

A reference to this kit in the 1972 MTSC no. 2.
http://www.imperialclub.org/Repair/Lit/Master/291/page06.htm

They recomend it for use in cars without internal fuel pump bypass that the owners are having hard time with hot starting.
Includes a picture of the kit on a pump.