[toomanybirds]

This distributor is advertised as an NOS unit, which it is. The seller also suggests it is correct for a 74 SD-455 which it is not.

http://cgi.ebay.com/ebaymotors/ws/eB...RL:MOTORS:1123

The 1112218 distributor was never used in a production car. It is the distributor that would have been installed in early production 1973 cars, but we all know the early cars were never built. The famous mid-year 1973 emission system change mandated by the EPA caused all of the distributors to be changed and new numbers assigned.

Again, the 1112218 distributor is not correct for a 73 or 74 SD-455 car. Part of the source of confusion for this distributor is that it was listed in the 73 parts catalog for the 1973 SD-455. No doubt, there were some distributors of this part number odered and sold, and that is why they are in circulation. If any cars had been built before the emission change, it would be correct for them, but they don't exist.

This distributor has some value for the parts, like the sleeve and gear, but has no value as correct replacement distributor for an SD car. (The vacuum advance is not the same)

1112205 is the correct number for both 73 and 74 SD-455 cars. The correct service replacement distributor is number 1112243.

This information is supported by GM publications and my experience. Anyone with different or additional info is welcome to post. I am always open to learning new things about these cars.

[rwinkles]

Great info toomany but 1 E6 = May 6, 1971?? This seems too early for anything SD. What's your take on the date?

[RAM AIR 1967]

My 1974 SD distributor has no date code or part # on it.

[toomanybirds]

Originally Posted by rwinkles

Great info toomany but 1 E6 = May 6, 1971?? This seems too early for anything SD. What's your take on the date?

I would say it is not unusual for a limited production engine to have parts made well in advance of its release. For example, the early 74 SD cars had engine parts cast in late 1972.

It is also possible the SD engine could have been considered for 72 model year production, or that the 1112218 distributor could have had another application that didn't make production. (I am guessing here)

A distributor with no number or date code has probably had the housing replaced. Replacement housings were unstamped.

[rwinkles]

I hear you, I've seen plenty of 1972 date codes on SD's. May 1971 is just a bit earlier than I would expect to see. I can't recall seeing anything else with a 1971 date although this is clearly the case for this particular part. Thanks again for the info!