[RockHillWill]

The FAM debate is always interesting to follow because of the varied 'opinions'. I am 73 years old and have never encountered an opinion that altered the laws of physics. I am reasonably familiar with chassis considerations and offer the following points.

Any bump encountered feeds the load into the chassis. Because the Model A axles are solid and share one spring at each end the load can often be multiplied. Original shocks offer little way in dampening these loads.

This load will apply itself mainly to only one corner of the car imparting a twisting load on the chassis. The greatest flex will occur at the weakest point along the chassis. If you look at the side of the Model A frame, you will see that the deepest section of the frame starts in front of the rear motor mount section and extends beyond the middle steel cross member. When the original motor mounts are in place it forms a 'boxed' portion of the chassis offering further isolation of load input along the chassis and isolating front suspension load input from rear suspension input. Also note that the bolt pattern for the rear motor mount plates is vertical as well as horizontal indicating a need to resist twist in that area. Also consider what the use is for the steel sleeves in that vertical section of the rear motor mounts.

If the original rear motor mounts are not used there is noticeable less flex resistance in that vicinity where both the firewall and the door hinges are located. I have noted multiple cracks in firewalls at the lower corners, even with original mounts. Consider what happens to the doors ability to remain latched if the front door hinges are allowed to move vertically with additional chassis flex. Drooping chassis make this an even more area for concern.

Often overlooked in this discussion is the concern for fore and aft movement when using FAM's. The fore and aft movement of the ENTIRE drivetrain is controlled by the rigidity of the rear motor mounts. The rear end transmits both accelerating and braking loads to the chassis thru the two trailing arms. They are attached to the torque tube that is attached to the transmission that is attached to the bell housing that is attached to the flywheel housing that transmits the load to the chassis when you either accelerate or brake. The same situation occurs at the front axle thru the wishbone thru the bell housing, etc. With FAM's, the entire fore and aft loading is controlled by the front motor mount (one small VERTICAL bolt) and the durometer measurement of those FAM's. This might seem of little concern if you are a VERY smooth and cordial driver and never encounter an emergency situation.

What might be the result if you backed up at only 5 MPH and hit a curb with one or both rear wheels? The body would tend to continue rearward, but that solid rear axle with stop in place, making the T/A, trans, hsg's, motor and WATER PUMP stop in place as well. The radiator is now part of the components that is still moving rearward. If you have more than an inch between the radiator and the water pump you might be OK, otherwise there is a significant risk of puncturing the rear face of the radiator.

Again this is merely a benign offering for your consideration. Personally, I feel that if you own a Model A, you should be able to do whatever you want to do with it to be able to have fun and enjoy it.