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Original Message
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| RE: Grading 427 Service blocks question |
| By Dave Shoe - 04/23/2001 3:40:59 PM; IP 12.2.11.131 |
I've sorta decided they did not grade engines. The mission of the blocks would most likely have been known prior to being cast.
The motor mount bosses on marine blocks would logically be flycut prior to boring, honing, and sonic checking the blocks, therefore 427 marine blocks would necessarily be "predefined" as marine blocks, not selected due to core shift, or whatever. Marine blocks apparently get their motor mount bosses flycut on the main FE production line - a line that destroys the side oiler passage to the extent the block can only be drilled as a center oiler.
Some race-only 427 blocks would probably have gotten a special softer iron alloy which would not necessarily be as durable on the street, but could handle extra pounding on the track.
I assume different nodular and nickel alloys would have been tried over the years, with the final batch of 427s (cast in 1972 at Ford's Australian foundry) getting a unique (and maybe new) "hi-phosphorous" iron alloy, an alloy I remain unfamiliar with as phosphorous is typically considered a contaminant in nodular iron.
The alloy selected would have logically been optimized for the application. Most 427 blocks, whether street, marine, or 427 industrial would have likely gotten their iron from the standard block line, because this alloy would be best suited to both durability and long life. I expect this alloy would have been either moderately nodular from the storage furnace, or the nodularity enhanced when pouring iron into the mold.
I'm still researching the layout structure if the Dearborn and Cleveland Foundries. I've learned a bunch about the Michigan Center already, and understand it had four grey iron lines and one nodular iron line. I'm also researching steels and irons, a topic which becomes interesting once the proper books are found.
One unique property of 427 blocks is that many of them from around 1965 through 1967 or so (my guess) also got stress relieved for about 24 hours in an oven prior to being machined. I doubt any marine or industrial motors of this period got the "oven" treatment (due to cost competition issues), but I expect many 427 street and 427 race blocks from this era did get the extra attention.
Shoe.
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This thread, so far...
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