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#1
05-03-2024, 12:10 PM
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Absolutely not 421 pistons. The valve reliefs are completely different on a 421.
The valve reliefs and dish shown are what forged 428 replacement TRW/Sealed Power 12cc pistons all look like. Pictured below, 421 piston with large reliefs and a 389 piston with smaller reliefs. The 421 used deep valve reliefs instead of a dish to lower the compression and enable the use of the same heads as a 389. The deeper reliefs aren’t there because the 421 cam had more valve lift (.407”} than the cam the 389s used.
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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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