Gonic GA-87 #11 to 209 conversion

I saw an old post by SPD635 that he stated he did a conversion on. SPD if you are there or if anyone else knows what it takes to switch from a perc cap to a 209, please help! Just a new nipple and nothing else? if so, where do I get the nipple? Have a GA-87 and want to switch it. Thank you.