SIG offered an engine support, primarily targeted to profiles I would guess, and it was some sort of black plastic and shaped like a squarish "C". I've used them and never noticed them compressing or changing in any way. This was at a time when SIG did almost all of their own plastic molding, so it was probably the same plastic (black) as their 4" bell crank. Top Flite used to make a similar product but smaller and intended to be used as one under each side. I have some of those also. Sterling , I think, used to make some plastic wedge supports the same way and were in varying degrees of angle to set engine offset for a profile. These were white nylon, it looked like, and while they worked OK, they were too thin and flimsy and would distort if they were not on a solid, smooth surface. Given that, though, engine heat didn't seem to affect them. If I were to try to 3D print something it would be similar to the SIG offering with about a 1 degree offset angle and make them in specific widths for specific brands of engines.
Type at you later,
Dan McEntee