The Ram Air main castings and other parts are not "special" castings in most cases, and may share the same part number in the small cast circle(s) as the standard units. In and after 1968 most of the Ram Air carburetors used an airhorn that is cut deeper and wider for the accl boot retainer.
Some Service Replacment units were not cut for the boot/retainer.
Service Replacment Ram Air carburetors will not have the plant code, and the Julian date will be later than the model year.
The most common SR Pontiac units were 7028276, 7029270, and 7040270. These were used to service Ram Air applications thru 1970.
They did not make any manual transmission SR Ram Air units that I have seen.
All original units will have a plant code after the number, and Julian date. If the plant code is missing, the carburetor is a restamp in most cases, unless it is a Service Replacement unit.
Since the value of the Ram Air units has soared, and folks are stamping standard castings with the intent to pass them off as originals, we do not give out secondary stamping information.
We get scores of units sent here, where folks have paid high prices for them, that were nothing but restamped standard units. Some of the work is very good, and will pass an initial inspection until we look closely at the rest of the carburetor. The vast majority of the restamped units we see have obvious features, such as a Hot Idle Compensator for example, which was not used on Ram Air units. We also see a LOT of Pontiac "Ram Air" units for sale with primary POE airhorns, another feature not used on Ram Air carbs.
My advice for anyone looking for a real Ram Air carburetor, would be to educate yourself in the features of the units, as most restamps are pretty obvious at a glance even if the number, plant code and Julian date look pretty good.......Cliff
