The way that Andymark advertises these gearboxes attached is with 4 sticks of churro connected with a single bolt on each side. Are there any better ways to attach these 2 things together, because there is no way a single bolt and some churro won’t bend or break under the force of the drive train this year.
I would start with a belly pan of some sort - that will add a bunch of stability by itself. After that, there are a bunch of options. You could do square stock across the front and back, attached with gussets. You could add a super structure to the top that everything else attaches to (especially if you have the bumpers attached to it to transmit force from being pinned). Just two that my team seriously explored in the offseason when we looked at these.