DISTRIBUTOR IDENTIFICATION

[Sheldon S.]

Can someone tell me how to identify a distributor without the ID band that should be on it? Are there any casting marks or dates? Thanks in advance. Sheldon

[Joe L.]

Re: DISTRIBUTOR IDENTIFICATION

Sheldon-----

Without the ID band, there is no way that I know of to positively identify the distributor. There are only a few different distributor housings used for 62-74 Corvette distributors and the GM PART #1851158 BY FAR predominates. Unless you've seen one of the rare ones(FI or ballbearing) what you've seen are the 1851158 type.

As I've mentioned previously, the only differences in Corvette tach drive distributors(TI or point-type) relate the configuration of the "auto cam" affixed to the top of the distributor mainshaft, the centrifugal advance weights, the centrifugal advance springs, and the vacuum control. However, GM "mixed-and-matched" these components to produce particular distributor configurations(and part numbers seen on the tags), so even if you could identify one or two of these components, you wouldn't have enough information to positively identify the distributor. In fact, even if you could identify ALL of the components, you would have a very difficult time determining what part number tag that the distributor originally "wore". I MIGHT be able to do it for you, but ONLY if you could positively identify BY PART NUMBER each of the components that I mentioned. Since only the vacuum control can be readily identified as to part number(assuming that the distributor has its original GM control installed or an exact GM replacement), identification becomes quite difficult.

And, understand that if any of the components that I mentioned have been changed during the life of the distributor, then the distributor is no longer the same part number that was on the original tag anyway.

The best way to "determine" the part number of a distributor is to CREATE one using KNOWN-BY-GM PART NUMBER, NOS COMPONENTS.

[Duke W.]

Re: DISTRIBUTOR IDENTIFICATION

If you can find an old distributor testing machine to determine the actual centrifugal and vacuum advance curves, you could then compare them to published specs, which could narrow down the possibilities. Of course, this assumes that it has not been modified over the years with different weights, springs, and vacuum can. If it's still in production configuration the actual curve data and identification of the autocam parts might narrow it down to a "most probable".

Duke