After messing around with the F-604 caps, I fitted and started to rivet one of the engine mount gussets in place. There will be one of these on either side of the firewall to spread the load out father than the steel weldment can do alone. Setting the rivets on these isn't much fun, bending over the side of the plane is hard on the lower back.
I added the second and third pictures for a friend of mine that was wondering what all support the engine mount, The second picture is of the right lower firewall weldment. The third picture is of the two center support that also attach to the engine mount. All the white parts are welded 4130 steel.
