16hp Briggs and Stratton opposed twin shaving the head

im working at a milling shop now and i am using the mill and would like to shave the head on my racing lawnmower motor im not sure how many thousandths i should take off so i dont blow a head gasket or break the heads of the head bolts off can someone tell me whats the best amount to take off?

U would have to really look into that cause of how far the head bolts go down. Will have smaller combustion chamber if u shave it down. I really wouldn't know about that.

Also thing about if u shaved it down it could bust the head cause of pressure.

Start at .005" and see what happens, measure the depth of your stud holes to make sure you can get proper clamp.

On OHV engines if you take too much you may have to mill the pistons to allow for valve clearance.

On Flatheads, the problem is similar and different at the same time. you need to open up the area above the valve to allow for flow and valve clearance.

And this would be the time to start looking at Higher octane fuels.

Don't bother, to risky if you ask me. You can always shim it after you take to much off tho but still.

One could also use a small die grinder (dremel etc) to put the 'fire slot' into the heads of the briggs flatties. I use that trick rather than shave heads. Doesn't up the compression but allows for a much better spark to be funneled to the combustion chamber (since there is a slight but noticeable offset between combustion chamber and spark plug location on the flattie). With a tuned carb and a good hot spark (I use E3 plugs for such a mod) one can gain a hp or more doing it, sometimes even more than that depending on other mods, fuel/additives used etc.

I understand now it's an aftermarket thing for smaller briggs engine mods, but its much easier to do it yourself (and a heck of a lot cheaper). Just use a copper gasket (or get the material and make your own like I do) and you're off and running...