1969 & 1970 GP 400 engines used that block code.
Check the date code by the distributor hole to better identify what block you have.
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1964 Tempest Coupe LS3/4L70E/3.42
1964 Le Mans Convertible 421 HO/TH350/2.56
2002 WS6 Convertible LS1/4L60E/3.23
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