When installing your engine mount, we tell you to set the mount on the extrusions leaving approximately .030 gap between the mount and the firewall, see Section IIL page 7. This is true if the mount is perfectly straight, however you should check to see that it is, by measuring from the firewall to the aft of the engine mount and verifying that the mount is at the correct fuselage station as shown in Section IIL page 14 for conical mounts and page 15 for dynafocal mounts.
Bear in mind that even though the mount is accurately welded up on a fixture, when it is normalized by heat treating, it is possible for the weldment to warp, creep or otherwise move enough that if you rely on the .030 measurement, you may have an engine that is not correctly located. Correctly installed, your engine crankshaft should be aligned with the zero buttline, plan view. Side view, the crankshaft should have 2 degrees of down thrust, (�. 1 degree) that is to say the spinner end is higher than the accessory case end.