Its supposed to be a 70 shaped cake for 40 people. Any ideas?
For a car cake to serve 40 I would start with 2 9X13 with single 8" sqaure on top and carve from there.
That gives you 55 servings to start with and 15 to carve away if you use Wilton's Party Serving chart,more if you do wedding size
It won't be exact but it will be close.