Only some of the e50 cylinders have open transfers, the hi-torque cylinders dont. The difference is in the manufacturing. Casting the transfers open with an all aluminum cylinder easier and reduces cost. I believe the sachs cylinder is cast this way as well, but it has a iron sleeve pressed in instead of plating directly on the aluminum. You would increase the transfer volume slightly, but at the same time the port window would remain the same. I don't think you would see any noticeable gain from opening the transfers alone, and I don't think it would be low end. I'd do a compression test. You want to make sure your rings are in good shape and that the decompression valve isn't leaking. Loss of compression will hurt your low end.