One of the greatest mysteries over the years has been the whole thing where Beaumont Sport Deluxe became a separate model during the production year rather than an option on a Beaumont Custom.
It's widely accepted that the transformation took place approximately December 1st 1966, i.e. any SD before that was a model 735 or 736 Custom with option A51 Sport package, any SD after that was a model 738 which was a Sport Deluxe and came only with a 396.
I am looking at the GM assembly manual microfiche cards tonight, just browsing, looking for "interesting" stuff.
I came across this page. My question is, if they already knew on 6-21-66 that there would be a 738 model SD, why did they not just produce it as such right from the start of production instead of doing such a confusing thing as switching during production? You can see in the picture, this information is for 73817 and 73867, which is Sport Deluxe hardtop and convertible.
It made a bit more sense when I thought the switch also meant going from sbc to BBC... But that theory went out the window with finding 396 powered 'sports optioned' cars... It's strange that sometimes SD/SS were options and other times had a unique VIN... Would be nice to understand why GM and Chevy bounced around.
