why didnt the first Holden motors have blue flame heads?

I have had a 1929 Chevrolet since 1969 and in the early years of ownership I collected all the printed information I could find on it and year models around 1929, including handbooks and what passed for an owners' manual, as well as hard cover books including "Sixty Years of Chevrolet" and years later, "Chevrolet, the Coming of Age" and I have never heard of a "Blue Flame Head" I understood that Chevrolet introduced the "Blue Flame Six" across the range in 1956. But I have been known to be wrong. Just ask my Wife

In 1937, GM released a new inline six with slight improvements in both durability and performance. This generation of six-cylinder engine is commonly known as the “Blue Flame” engine. “Blue Flame” was an advertising term used by GM in the ’30s and ’40s to describe the efficiency of GM engines. According to the advertising guys, a blue flame (rather than yellow) meant perfect combustion was being achieved. The name was actually only used on specific engines from ’53-’62, not the entire generation. This engine was used in multiple different applications, and was produced in various displacements. The most popular I-6 from this era was the 235 ci. This engine was used in the majority of GM cars and trucks from its introduction in 1941 to 1955, when the Chevrolet small block V8 was introduced. 235s offered great economy and reliability, as well as good performance for the time.

From another source
The next-generation Chevrolet inline 6 was introduced in 1937 and phased out in 1963 in the US, and 1964 in Brazil. It is often known as the "Blue Flame" engine, although that name was only officially applied beginning in 1953, and then only for one certain model of the engine.[1]

And from another source
The use of "Blue Flame" was a sales gimmick referring to the Chevrolet clean burn method, not an engine name until the 50's.
The first ads using this description were when the 1937 Chevrolet touted “the blue-flame principle of fuel combustion” as Chevrolet’s answer to increasing efficiency and economy.

There was little new or revolutionary about a Blue Flame Engine combustion system and all its features could be found on many engines of the period. Comparison can be made with the huge advertising campaigns by Chrysler and Ford for their "Hemi" and "Cross Flow" engines respectively. Both features were in production on many vehicles around the world continuously from the 1890's. The marketing men are there to create legends (and sales).

All petrol engines burn with a blue flame,unless they are burning significant oil...............I read Chev first used the blue flame claim in advertising in 1934 in response to Ford making high speed colour pictures of engine combustion thru clear panels in cylinder heads...........the pictures were widely published in magazines of the time ,not just car mags....Obviously with a OHV motor it wasnt possible to make similar pictures.....But a while ago I was shown a 1929 magazine reference to a blue flame head on the new Chev 6 engine....Of course you can see blue flame in any running engine by taking the exhaust off, like we used to do with a BSA motorbike back in the sixties and ride around with no exhaust.....we were pretty well known .

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.Isnt it called a ….. BLUE FLAME..... When you bend over with a match at your rear end ,,,,,!!!!!!!!!!!!!!

……………….Billy...………………….

Billy, Only if you fart...

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Another version of a grey Holden head...…………..
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www.whichcar.com.au/features/1952-holden...h-a-waggott-twin-cam

…………………...Billy...………………..

.Another shot of the modified grey Holden donk...……………





………..........Billy.......................