The bowl vents through that groove. If you don't run an insulator you need to vent the bowl a different way.I
I have seen some that the little groove in it was filled with like epoxy and then sanded down, what is the groove for and it seems like you don't need it in there.
yes I was just going to say if you're running rwyb and show up with a 212 and stock carb the isolator plate is gonna be the least of your concerns.....out to lunch!Now that I think about it, I don't think I have ever seen anyone run a 212/clone carb on any small block motor in rwyb or small block open. They all use bigger carbs- 390 carb, Mikuni, Lectron etc.