IMO a 3:36 is too high for a 216 if thats what you have in the Burb. 57' cars were originally equipped with 3:36 for V8 A/T and even V8 3 speeds were 3:55 or 3:70 in tri-fives and 6 cylinders were 3:70-4:11 range so that's why I doubt it's low enough for your application.
You don't say what engine you have so maybe you've already researched this and understand what is correct.
