Yesterday I trailered a '69 350/350 Monaco Orange coupe with 79k original miles from San Jose home to Seattle. The car is October '69 build #32444, sold new by Harry Mann Chevy in LA (so says POP). Practically every mile, tank of fuel and service has been recorded in 2 previous owners "little black books", so I'm pretty sure it's mostly original (except starter, H2O pump, battery, smog pump, etc.). Upon checking the engine codes, I discovered that rather than a casting date, the car is coded "M47" where the date code should be. I read an article in the restorer by Gene Gamache, that explains the "M" code blocks were "specials" the factory used for experimenting on ways to improve the production process.
In addition to the odd date casting, the car also has a 1-12-9 date on the intake. Also, the left cylinder head is casting 3921786, dated 1-19-9 (read the #'s thru the oil filler hole). This number falls in line with the intake casting - so based on the cars documetation I'm guessing the right head is dated close to the left. Both intake and head(s) have a January date, obviously very late for the Oct. build date.
Could this engine have been a "test" engine early in the year and kept off to the side until the end of the production year when it was installed? Can anyone shed any more light on the "M" coded engines? Or why such an early intake & head(s) might have been used?
In addition to the odd date casting, the car also has a 1-12-9 date on the intake. Also, the left cylinder head is casting 3921786, dated 1-19-9 (read the #'s thru the oil filler hole). This number falls in line with the intake casting - so based on the cars documetation I'm guessing the right head is dated close to the left. Both intake and head(s) have a January date, obviously very late for the Oct. build date.
Could this engine have been a "test" engine early in the year and kept off to the side until the end of the production year when it was installed? Can anyone shed any more light on the "M" coded engines? Or why such an early intake & head(s) might have been used?
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