Well I looked in my training manual and Service bulletins on ignition
timing, and no joy to be found on dates. So, best answers I have are based
on personal experience, not on any official word from the manufacturer.
Sometime in the mid 70's, GM introduced HEI ignition on SOME brands and
models. It was not a Corporate wide roll out. Premium brands and models got
it first.
About the same time they rolled out CCC. Computer Command Control.
They were not forthcoming with service techniques AT ALL until the
Independent Garage Owners Association, and Motor's, Chiltons, and other
publishers of aftermarket spec manuals threatened lawsuits over it. Scope
manufacturers like Snap On, Allen Smartscope, Kent Moore, and others joined
into the fray, and GM claimed Copyright infringement, proprietary trade
secret rights, and a bunch of delay tactics. It wasn't until the D.O.T.
reared it's ugly head that some relaxing of tightly held specs came about.
As an Independent Machine Shop owner/partner, I had daily contact in
this fray. All the big 3 auto companies had their own version of this
story.
Along came OBD 1. On board diagnostics, version 1. Then, OBD 2, then
CAN, and on and on. The foreign manufactured cars had their own stuff, then
were forced to comply with OBD 2.
In 1977, I went to work for Department of Corrections as a Vocational
Technical Instructor. Dept of Education required certification, so, back to
School I went every summer until I retired. GM had a training site in
Tigard, Or and I attended that until they closed the center and went to
online training. Many other service schools, too many to note here. None of
the literature I still have, has dates when the magnetic probe timing setup
first arrived. So, best guess is as Rob says, when they changed the part
number should be as close as anything I have.
Jim Hupy
> Gary,
>
> That lines up the
>
> Ref: Parts Book 78Z / Section 8 / Page 8-4 / Figure 8.005 - Cylinder
> Block, Crankshaft and Oil Pan
>
> Key 33 - P/N 403902 - Indicator - timing (1973)
> Key 33 - P/N 419048 - Indicator - timing (eff. w/ 1974) (repl. 417140)
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Gary
> Kosier
> Sent: Friday, February 16, 2018 9:39 AM
> To: gmclist
> Subject: Re: [GMCnet] 403 timing tab
>
> Jim,
>
> According to the Oldsmobile parts book, the pointer is listed as 68-73 all
> the
> same and 74-78 all the same as far as the 455 and 403. Now with GM, there
> is always the possibility that the had an earlier part number and
> superseded
> it without leaving any evidence.
>
> Gary Kosier the old parts man
> 77PB w/500Cad
> Newark, Ohio
>
>
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