[Dan Jensen]

The '72 service manual was never updated to incorporate the changes made to the '72 455 H.O. carbs, i.e., they had the booster rings like the rest of the '72 lineup. The '72 service manual is doing a disservice to those with '72 H.O.s. I've seen a number of '72 H.O. carbs (7042270 and 7042273) with correct date codes, and they all had booster rings. No doubt they were re-installed to help the H.O. meet tighter emission requirements.

The '71 7041263 400 manual trans carb has been a hot commodity the past few years as more and more people (like '71 H.O. owners) have discovered that it was a cheaper alternative to buying the "real" thing. Because of its sudden popularity, its prices have risen as well, but not to the extent of the H.O. carbs. I have several of these 400 carbs that I bought from the local speed shop, all without the booster rings. Most were plumbed for a transmission vacuum modulator during remanufacturing! (Sorry, these carbs have been sold out for a few years now.)

I hope this clears up some of the confusion!