orange or chrome ecu box?

I have a 74 318 in my 72 Barracuda.....need to get the ecu box.....I am not sure how the motor is built.....but I was told it was rebuilt to factory specs 5 years ago.

Should I get the orange or chrome box, as I see the chrome has "a hotter spark".......its only a $20 difference but if it is wasted $$$ why spend it....
Thanks guys.