YDubbs

Hi, does anyone know when GM made the switch from 1100900 to 1100543 alternator number? I own an early 1971 pre 4000 (Sept 1970 build date) and have a found a 1970 alternator but with a 1100900 number not 1100543 (which is for a 1971). Most of the original parts in the car have an August date code. Could it be possible that GM may have used a 1100900 alternator toward the tail end of 1970 production vehicles? Again my car was assembled in Sept 1970 so it makes sense that a lot of my parts have an Aug date code.

7T1vette

Definitely possible. GM would have used left-over stock for "general" items like the alternator...if the one for the new model year was very similar and interchangeable. Some model change items are "MUST" changes; others are "USE" changes.

Easy Mike

Mike Ward

What's the assembly date of the 1100543 alternator?

YDubbs

I don't have a 1100543 alternator yet but the build date of the 1100900 alt is 0G30. Assembly date of my vette is Sept 1970.

Mike Ward

0G30 is July 30 1970. Works for me unless there's some fit, form or function reason that it cannot have been used on a '71. Maybe Stan will comment.

YDubbs

Most of the original parts are coded the first two weeks of Sept. Block is first week of Sept, the proportioning valve (t-valve) on the breaks are Sept 13th 1970. My guess is that assembly started in Sept then postponed mid Sept through part of Oct. Car rolled off assembly line first week of Nov. 1970.