Engine rack recommendations for trailer

I’m really tight on space in my trailer. Any one have any spare engine mounting setups? I have extra motors and I always end up throwing them in the back of my car. Id rather keep it all in my trailer… here’s how limited I am on size. (Older photo I have 3 more tire racks on the left so that’s out of the question now lol.

I’d clean out the bottom of the blue toolbox and put a plywood platform there with carriage bolts and wingnuts that hold down a couple of strips of wood to hold the engines down… or do similar below that short tire rack in front of the spare tire.