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Old 01-02-2008, 04:54 AM   #12 (permalink)
Oldsguy
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Join Date: May 2004
Location: Lees Summit MO
Posts: 3,145
The nickel content statement is fact, the legend part is that everyone needs one and it is better to have in your build.

"Big Block Functional Differences

For those seeking to build a really heavy-duty engine, rumor has it that the blocks with an "F5" or "F6" cast on the rear face, under the flexplate area, are higher in nickel, and stronger. These are commonly 1967 to 1970 or so 425 or 455 blocks"
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'77 Cutlass Supreme
'46 2 door
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