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Old 01-21-2023, 07:45 PM
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If I were to replace the 326 HO 4 speed in my 66 LeMans would you go with a 389 or a 400? What advantages does the 400 have over the 389?


Last edited by arbys; 01-21-2023 at 08:06 PM.
  #2  
Old 01-21-2023, 07:58 PM
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I like 400 engines, but the 389 would be more "period correct"


Last edited by Mr Twister; 01-21-2023 at 08:06 PM.
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Old 01-21-2023, 08:22 PM
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Eleven cubic inches plus a better cylinder head and valvetrain design.

The availability of pistons that are reasonably priced is a big advantage for the 400 engines, good 389 pistons are scarce and expensive in comparison.

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  #4  
Old 01-22-2023, 05:56 AM
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1963 and earlier 389 blocks wont hold the starter.
1964-66 389īs may be bored out to 400 std.

400īs is still plentiful, 389īs is not.

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Old 01-22-2023, 12:53 PM
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65 and 66 389 have thin wall cast blocks, plus the connecting rods were strengthened in 1967 over 1966 by adding a rib on the big end next to the rod bolt.

Then there's what Bart said about the heads, and valvetrain being improved also. Unless you needed to have a 389 for class rules, I would go for a 400, hands down.

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  #6  
Old 01-24-2023, 06:49 PM
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A '66 326 HO 4 speed LeMans is a rare enough bird (and way cool) that I would leave it alone. Put an 068 cam in it and bolt on a tri-power and you're all set.

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  #7  
Old 01-24-2023, 10:58 PM
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I vote leave the 326 HO in and build that up some. But if you must, just go to a 400 stroker then.

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Old 01-25-2023, 12:43 PM
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