Tim,

it doesn't help much to talk about offsets here and there without having a 0 degree reference. Either your FW was installed per plans with both the down and right thrust or it was installed square to the fuse sides - both vertically and horizontally. For a 0-0 (right-down) setup, the FW wants to be square to the thrust line and perpendicular to the work bench (assuming it is flat). There is nothing that one can "build in" to a firewall to introduce engine offset, it is in how you install the FW with respect to the fuse sides. The only thing that can be done to aid in introducing the FW offset is to bevel the edges to the correct angle so that when it is installed at the, say, 2-3 degree offsets, then, when you mount your engine, no spacers (washers) are needed.

You should remove your engine and check whether your FW is square with respect to the bench (this is for down thrust offset) as well as square to the thrust line. If it isn't, you might have accidentally introduced excessive angles already into the FW installation and using washers to further offset the engine is resulting in what the picture seems to depict. You may actually need to introduce washer on the opposite side to counteract excessive built-in offset.

I find that the only reliable way to build in offset angles when installing a FW is to actually measure and mark the fuse sides for down thrust angle as well as where it should be bonded with respect to each side. Of course this is much easier to do when the fuse has yet to be framed up. In the absence of this, it can be somewhat tricky to get those angles right. The FW side edge lines on the fuse sides will tell you where exactly the FW should be bonded. You then merely mount your engine flush against the FW by placing it in the appropiate corner in the upper right quadrant of the FW (when looked at from the front).

A protractor like Ralph suggested would help, you'll be able to measure it rather than eye balling it. It's pretty hard to gauge 2-3 degrees. 30, 45 or 90 are obviously a little easier.

David.