Hi David, Here is a few photos so you all can see what the 4 bolt 25cc Poulan Featherlite looks like, before they went to the 2 bolt backplate, a bolt on muffler (I think) and a different design carb spacer. I started the conversion on this one for the photos. This engine is about as easy to remove the flange on as a Toro. For reference the flange part removed that you see in one piece weighs 2 and 1/8 ounces. I leave part of the flange supports on as braces for the crankcase snout, which is easy to do. If you grind them off you will only remove a minute bit of weight. You do need to open the ports on these. I open the intake a lot and try not to compromise the carb pulse hole. The exhaust port needs a bit of squaring up and the muffler needs to be opened up. The single needle original carb needs to be replaced with a 2 needle also. I tried the single needle carb for reference and didn't get very high revs from it. For reference, the original carb from a 25cc has a 1/2" bore and a 8mm venturi. the Zama I use is a M29D - 86A with a 9/16" bore and a 9.5 to 10mm venturi. (Hard to measure without removing the choke.) In general I think these are nice fairly light weight and compact engines. They can still be found for reasonable prices. I got 8000 RPMs from my first 25 like this one with a 16x8 MA Classic and want to see if I can duplicate the performance with this one. I ran this before starting to convert it and it sounded very encouraging. Someone broke the Trimmer shaft on this one before the engine had much time on it. This is a common occurance with these. My first one had the plastic shaft mount broken off before it was ever run. I got them both off of ----.