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Thread: 35hp Evinrude High Compression Head question

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    Default 35hp Evinrude High Compression Head question

    I believe I found a high compression head from a 1982 35hp evinrude on Ebay and went ahead and bought it. Looks like it has the almost 360 degree squish band that its supposed to have. Can I bolt this on to my 1994 30 evinrude without making any additional modifications? Also, does anyone know where I can purchase larger main jets for my carburetor? Looking to make my cowling breathe better and don't want to risk running lean.
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    I too bought one of these heads after reading on here about the extra compression. I did a compression test on my stock 1994 30hp and got 118psi in both cylinders. I put the 1982 head on and sadly only got 105psi. I milled it a bunch (maybe 0.060”) I can’t remember. I had to reshape it inside a little to fit the the pistons. In the end I was able to get 165psi on a 0.040” over block. I use 93 octane mixed at 40:1. Stock timing. 63 jet. Here is a video of planing a head. https://m.youtube.com/watch?v=ooG2ZI6Wdys
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    Thank you for the reply. I haven't put mine on yet, but I've been told that a lot of the new head gaskets are "low compression" gaskets and are thicker than the ones from 82. I don't remember the part number off the top of my head, but I think the thin one is still available. I may try that before milling anything off my head.
    Did you notice any performance gain after getting the compression that high?

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