Bob, Since nobody answered with definitive information, let me offer the following: I run with this carburetor on my Avatar coupe. Why? Because wanted a bit more cfm than what a single 94 could provide and didn't want to go with dual carbs as I was running the loadamatic distributor and didn't want to mess up the advance that was dependent upon the venturi vacuum that a 94 or this Mercury carb could provide. I realize much has been written and said about the two vs. one carb vacuum situation but decided to go with this type of carb as a reasonable compromise. Another factor was that it was a bit different. That had appeal to me. Similar carbs can be found on Lincolns and a number of trucks had them with governors and such. I believe there was an Oldsmobile version at one time. A third factor in my decision was that I had a nice Mercury Canadian aluminum intake that polished up nicely and figured that with the 4 bolt pattern on it, it was a natural to use this carb. On the negative side, not many people can work on them. Before I met the right guy, (Charlie NY) I had the carb back and forth to another rebuilder severallllll times before he got it right. I wish I knew more to share. Having this on my ride going on 14 years, I can say it has worked pretty well and provides me with the "different factor" I was looking for.
Thanks AVater! I got the carb at the Sunday flea market from one of the regular vendors. I've bought stuff from him for years and try to keep people happy. One small tag has GM stamped on it so maybe it is an Oldsmobile item? Hope it has a one way trip to Hershey in October.
Used on Mercurys, Lincolns, and, with a governor, several trucks. Never used on Oldsmobile. A similar appearing Rochester was used by Oldsmobile in 1949 and 1950, and thankfully discontinued after the 1950 model year. The Rochester type was "AA". The Holley passenger type was 885-FFC ("C" as in choke). The Holley truck version was 885-FFG ("G" as in governor). EDIT: was called away from computer before finishing post. These 885 style Holleys are the forerunner of the "Haystack" Holley, a.k.a. "Teapot" Holley. They share the same design, but with an enclosed air intake, where the later 2-barrel and 4-barrel haystacks have an open air intake. Many parts are interchangeable. from the 885 to the 1901, 2140, and 4000 series. Jon
Some Olds V8s also came with a Carter version, with an oval air inlet. I used to have a stamped steel adapter that allowed the use of the Rochester type air cleaner with a round opening with the Carter carburetor.
The Oldsmobile Carter version was a variety of Carter's standard type WGD, but with the 90 degree air intake. The WGD was used on Buick, Pontiac, Olds, Hudson, Nash, and others; while the Rochester AA (thankfully) was unique to the 1949 and 1950 Oldsmobile. A picture of the Carter and the adapter mentioned by Heathen may be viewed here: https://www.thecarburetorshop.com/Carbshop_virtual_museum.htm#Carter And just for the record, Stromberg also had a version of the WW with the 90 degree air intake (Studebaker) and before that EE-3's on Packard and Stutz. There are others. Jon
Does anyone know the male thread size of the fuel inlet fitting for this carb? I've tried to research online, but get differing answers. I think it's 9/16-24 can anyone confirm?
I can confirm that Holley part number 19R-92 used on the ORIGINAL 1949~1951 Mercury carburetors was 9/16x24. The factory service replacement carb for all three years (R-690-A) used a different fitting. I do not have one of these fittings to measure. Jon
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