87mm is what you are looking for. I bought mine from Honda of Troy's ebay site for a fair price. I also got my stg 1 hotcam from them too. As far as brand of piston I've been a loyal Wiseco guy for 15 yrs but the JE would be the premium choice. You will want the Cometic 89mm gasket set, the 86 is just too small. The stock header is a fine choice for this combo but you will want to do the header mod to get max flow out of it. For jetting if you are running a 138 main with success then figure starting with a 148 when you get this combo together. Most likely you will be fine with the stock pilot but a bump to a 40 would not hurt. If you find any hesitation in the mid after all this then bump the needle up one clip (move the clip down on the needle).
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