Thanks, Silversurfer. At one point, I was curious about whether or not the left thrust was caused by the motor mounts or the angle of the firewall. So I kept the motor mounts attached to the engine, but removed it from the firewall. I then put the engine and motor mounts on a flat surface with the crank sticking straight up. I placed a straightedge on the prop washer and then measured from each end of the straightedge to the flat surface. The measurements were the same. So the firewall must be out just a bit. I put two #6 washers between the firewall and the left side motor mount (viewed from sitting in the cockpit- that was quite a squeeze getting in there). This makes the crank just about perfectly straight. I will take your advice about bringing washers along with me so I can trim out the thrust angle if I need to during the first few flights. Thanks.