What did they do before the AIM change

[Edward M.]

OK, another how did they handle things question.

What did the factory do before the AIM change occurred.

I am thinking specifically about the 1956 single four barrel Corvette. The Chevrolet Bulletin dated April 6, 1956 announced the single four barrel engine as the standard motor. The two four engine became the optional engine.

The AIM change to reflect this is apparently dated May 28, 1956.

OK, let us assume for a moment that Chevrolet did build single four cars prior to May 28th, 1956.

How did they do it? What procedure did they use? Or is it absolutely impossible for single four cars to have been build prior to the AIM change.

[Jack H.]

Re: What did they do before the AIM change

Noland Adams talks about this in his Vol 1 book (pages 123-125). He concludes things are 'muddy' but pieces together a couple of facts:

(1) There were two versions of the 225 HP, 2x4 setup (early and late, with the early version having discrete chokes on both carbs).

(2) The sales literature stated the 225 HP version of the engine was the option and the 210 HP version was the base engine from the git go...

(3) He speculates that base engine cars simply weren't available until after the start of production when the AIM change was made to call out the 2x4 setup as option RO 469.

Whether the factory 'substituted' 2x4 engines for those in the order queue with 1x4 configurations isn't clear...

[John H.]

Re: What did they do before the AIM change

How did they do it? What procedure did they use? Or is it absolutely impossible for single four cars to have been build prior to the AIM change.

Ed -

The A.I.M. was an Engineering-issued information document used as an assembly aid; it was NOT a "process" document. It showed what was to be done, not how it was to be done, and '56 was the first year for the A.I.M. as we know it.

It's entirely possible that 1x4 cars were built prior to the announcement and the A.I.M. didn't "catch up" until later; verifying that would have to be based on seeing known-original 1x4 cars with serial numbers placing their build date prior to the April announcement.

[Edward M.]

Re: What did they do before the AIM change

Thanks John, that is what I kind of figured.

You would happen to know where I can get my hands on the 1956 AIM, before the 1957 revisions were rolled in, would you?

[John H.]

Re: What did they do before the AIM change

You would happen to know where I can get my hands on the 1956 AIM, before the 1957 revisions were rolled in, would you?

Ed -

Nope - I've never seen one that didn't have the '57 updates. In the plant, when the updated sheets arrived and were placed in the binders, the obsolete sheets were trashed; the plant didn't care about how they were built last week - only this week and beyond.

[Art A.]

Re: What did they do before the AIM change

Ed -

The A.I.M. was an Engineering-issued information document used as an assembly aid; it was NOT a "process" document. It showed what was to be done, not how it was to be done, and '56 was the first year for the A.I.M. as we know it.

It's entirely possible that 1x4 cars were built prior to the announcement and the A.I.M. didn't "catch up" until later; verifying that would have to be based on seeing known-original 1x4 cars with serial numbers placing their build date prior to the April announcement.

Of course John is right on..............as usual. I might add that each and every part ( and assembly) was RELEASED into the system by Engineering via an ECA, Engineering Change Authorization. The ECAs detailed all of the necessary information for the downstream users. There were 20 items that the ECA addressed, including release dates, reason for the change, effective point, disposition of stock...............etc.

The ECAs were the bible for items going into and out of production.

When I left GM in 1999 they still had many file cabinets full of old ECAs. I don't know if they are still around or if they got computerized, as most of GM's documents did.

[Mike M.]

Re: What did they do before the AIM change

art: hard to believe you've been gone from GM for 10 years. might explain why GM's has had its teats in the wringer for the last year(or more). regards,mike

[Art A.]

Re: What did they do before the AIM change

art: hard to believe you've been gone from GM for 10 years. might explain why GM's has had its teats in the wringer for the last year(or more). regards,mike

Mike
Yeah, a lot more than a year. It is hard to believe it will be 10 years next November. I used to jokingly say GM will fold when I retire. See I WAS the most valuable GM employee.

ED
BTW Chevrolet did have AIMs for the Corvette starting with the 1953 MY. Well sort of...........they were called Corvette Assembly Instructions, CAIs, however they were NOT in the Manual format like the AIMs. They were actually individual drawings, each drawing had it's own part number and were issued only to a department or group that effected them. For example, body CAI's would only have been issued to the Body Group, engine related CAI's were only sent to the Engine related Groups......etc. When I was doing research within GM I always on the look out for a "master" listing of ALL of the part numbers for the CAIs but I never came across one.
If you notice in the 57 AIM you will find some sheets (pages) that are actually two sheets for the same item. This is a carryover from the CAI format. Also notice that the 57 AIM, (as we call it nowadays) that you might have in your possession, is actually titled (above the revision block) Corvette Instruction Manual.