G16 Starter bracket loose

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The starter belt was slipping on a G16. Noticed that the starter bracket was loose so tried to tighten the bolts. Apparently it's been loose for awhile as the bracket had worn the bolts and when I tried to tighten them the heads came off. Tried to drill and easy-out them to no avail. **** near like they welded themsleves to the aluminum block. Drilled them out and going to Helicoil them. My concern is that the steel starter bracket has worn away some (1/8") of the mount. More on one side than the other. Should I worry about this unlevel mount of the starter? I could shim it with a fender washer if it's deemed necessary. Thanks for any advice.