401 compression ratio/head milling question

[Magical_Merlin]

I have a '77 401 with the 8.25 CR and a set of 502 heads. How much can I mill off the heads to bump up the CR and not have to mill the intake manifold? Thanks.

[jeepsr4ever]

.023 will give you 1/2 point in compression. You shouldnt need to modify your intake for this. You may need .020 shims under your rocker bridges.

[Henry Lavrenz]

just a fyi, when you mill the chamber side of a set of heads you usually mill the intake side of the heads, not the intake manifold. This way the heads will work with and stock manifold. Hankrod aka Hackrod :wink: Matt

[jeepsr4ever]

just a fyi, when you mill the chamber side of a set of heads you usually mill the intake side of the heads, not the intake manifold. This way the heads will work with and stock manifold. Hankrod aka Hackrod :wink: Matt


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