The Echo SB-1080 shortblock is the basis of the BME 50. If you are going to buy something then buy one of these. Of the 20 or so conversions I have done this is the best by a mile. It has everything going going for it. It is light weight, beam mount, and no goofie carb attachment work arounds. If you want you can buy everything you need to "convert". Get a NOS 13 or 15mm walbro carb that has an accelerator pump. Check on EBAY for a NOS carb.