valve spec differance.

5 replies to this topic
  • potman1980

Posted April 19, 2012 - 12:28 PM


hello :thumbsup:

my wr 400 has eaten its own big end and i'm thinking of doing the old bore out job on it. i have seen a few threads on here about doing the 426 conversion, but having seen 98mm big bore piston kits for sale for the 450 i have decided to have a go at somthing different.

i was wondering if any one knows the valve sizes of the 450 head compared to the 426 and 400, or were i could get this information.


  • GCannon

Posted April 19, 2012 - 03:06 PM


Valve size for the 400 and 426 are the same. The 450 valves I belive are shorter and the entire Head was scaled down to save weight. There are a lot of dimensional differnces between the 426 and the 450.

  • potman1980

Posted April 19, 2012 - 10:20 PM



does that mean i can't fit a 450 head on a 426 cylinder?

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  • GCannon

Posted April 20, 2012 - 02:10 PM


Yes: I am pretty sure your timing chain will be too long. Among other things

  • grayracer513

Posted April 20, 2012 - 02:22 PM


Even if that were not true, the 450 head will not bolt to a 400/426 cylinder.

  • potman1980

Posted April 21, 2012 - 09:07 AM


but will a 450 cylinder fit onto a 400 crank case?


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