Measure your flex plate across from center of one converter bolt hole to another. I just did this with my 904 and my stock flexpate was 10" center to center. I upgraded to the B&M and TCI streetfighter converter. Those both had the same 10inch mouting dimention. Whatever converter you decide to buy the specs with tell you the flex plate mounting bolt dimentions. Probably no need for you to get a new flexplate unless since it is apart an upgrade is easy.
My order last week from summit with a nice 3000 convertor.
TCI-142300 http://store.summitracing.com/partdetail.asp?autofilter=1&part=TCI-142300&N=0&autoview=sku