Leroy’s indicates that .100 spaghetti is to be used but I found some .103 not much bigger but it did the job on a 5.5hp. Permatex aviation gasket sealer was used in the grove and under bolt heads.. Pressure and vacum tested good
…Yes the first ones are a pain
especially when the shock absorber on the 5.5 is stretched making fitting impossible. I got it spot welded. 
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