Ahh, the weight and balance! To be honest, I did not weigh the engine prior to installation. I pretty much took Rotec's word on the dry weight of the engine with all accessories to be 232 lbs. After the installation was complete, I put it on scales and did a rough W&B. It was obvious from the start that there would have to be some adjustments made for the Model IV. Not until after completion and paint did I do any serious work. What I wanted was the worse case scenario of a 100 pound pilot who runs out of fuel, and no baggage, to still be in the CG envelope. To do this I had to add a 5 pound lead weight into the tail. So I made a shelf large enough to accomadate two five pound lead ingots that dove tailed together and placed the shelf over the tailwheel attachment. With one installed it was on the forward end of the CG limit at worse case... with the second one installed, it really improved reduction of the stick pressure on round out. Now I can go full fuel, two 170 pound individuals, and 40 pounds of baggage... all still in CG but that takes me a little over 100 pounds over gross. No way to go out of CG forward or aft if loaded below gross weight limits. In retrospect, I would place the battery and any other weighty object of use as far back as possible, keeping in mind accessability for maintenance. Not much room in the Model IV for that, but the later models might be better. I did not want to cut fabric and install an access door on the side after all was done.